Talk:Caffeine/Archive 5

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Archive 4 Archive 5 Archive 6


article quotes in german/(french?)

this is the english wikipedia why is there quoted articles in a different language? (talk) 03:59, 9 March 2011 (UTC)

Caffeine makes me run longer?

Will I last longer in a 2.4km run and get a better result for my NAPFA test if I drink coffee before the run? Dsdsasds (talk) 13:22, 20 December 2010 (UTC)

Quitting caffeine

I quit caffeine in 1984. My symptoms were that I slept for two days (like having a severe influenza) and then had uncomfortable feelings (feelings like walking in a fog) for several months. This is 100 % fact, it did happen to me and I am not a person who fakes facts. I added this to the article about Caffeine, and it seems to have been immediately deleted by someone. I added it again, will see if it again disappears. Jacob Palme —Preceding undated comment added 00:37, 16 July 2010 (UTC).

Thanks, but wikipedia can not accept original research, it is just against its basic policies. Many reasons for this are obvious and listing them would fill up this page. Materialscientist (talk) 00:45, 16 July 2010 (UTC)

Research shows that caffeine may increase performance on boring, repetitive tasks but it has failed to show improve memory or improved performance in complex cognitive tasks. (Smith 2002) —Preceding unsigned comment added by (talk) 17:18, 7 December 2009 (UTC)

Commonly Used Caffeine-Containing Plants

The most commonly used caffeine-containing plants are coffee, tea, and to a lesser extent cacao. [1]

First off, coffee and tea aren't plants. Second, I don't see anything related to this sentence in the citation, but I can barely read the citation so yeah. I can't think of any way to fix this without messing up the flow of the paragraph, so I'll leave it here.Ziiv (talk) 02:03, 1 July 2009 (UTC)

I think the current version clears up your concern. Josué L. Barbosa (talk) 04:46, 17 January 2010 (UTC)

Caffine and Stunted growth. Main article inaccuracy...

- Regarding the mistaken conclusions of Nutritionist Joy Bauer cited in the main article.
- Caffine intake stunts the development of long bones. This development has nothing to do with osteoporosis, which is caused by a decrease in density of bone tissue. - Caffine intake slows osteogenesis, conducted by osteoblasts, at the epiphyseal plates of the long bones thereby retarding their growth. The long bones begin growth at conception and continue to grow (on average) into the early to mid twenties. The consumption of caffine durring this growth period will stunt the bones growth by reducing the amount of new bone created at the epiphyseal plate. There is little in the way of long term scientific study since the inhibitory effects can only be measured after the fact. Stated simply, caffine slows bone growth along the long axis. The diminished action at the epiphyseal plate may not cause osteoporosis, but less growth means that the long bone will not form to its full potential. —Preceding unsigned comment added by (talk) 03:53, 6 July 2009 (UTC)

Are there sources to back up these statements? Looie496 (talk) 05:15, 6 July 2009 (UTC)
  • Reference 104, citing MSNBC, is not conclusive and may be considered somewhat misleading. While the Author, Nutritionist Joy Bauer does indicate (by the title of the article) that she has reached the conclusion that caffeine does not stunt growth, the statements and supporting data referenced within her article seem to counter this claim. For example, "Research suggests that coffee consumption has no effect on height." This statement in itself does not indicate that conclusive evidence to the contrary has yet been discovered.
  • Additionally, the article continues by disputing the specific findings that Joy Bauer based her conclusion on; "However, much of the previous research that linked caffeinated beverages and osteoporosis were made in populations that also had low calcium intakes. These people were more likely replacing calcium-rich milk with coffee or caffeinated sodas." This seems indicative of a high likelihood for inaccurate findings in the conclusions of the study.
  • Lastly, the article hints at recent findings that studies have proven caffeine to limit or prohibit calcium absorption in bones; "More recent studies suggest that even if caffeine does offset calcium absorption, the effect is both slight and easily offset by adding some milk in your coffee." Further supporting evidence that caffeine indeed has an impact on the absorption of materials that directly impact bone growth.
  • With this in mind it seems that the article actually contains more information in support of the claim that caffeine can potentially stunt growth, despite the fact the author titled the subject otherwise.


  • Reference 105, citing, is not conclusive and may be considered somewhat misleading. The article contains only the following entry on the subject, "One thing that caffeine doesn't do is stunt growth. Although scientists once worried that caffeine could hinder growth, this isn't supported by research." This statement does not indicate that any conclusive evidence for or against the argument. The statement seems to indicate that no conclusive findings support the claim, but neither does it provide evidence to the contrary. Additionally, the research and study are not referenced, making them difficult to verify. (just because research does not support a specific claim, does not automatically indicate a conclusion to the contrary)
  • With this in mind it seems that the article makes an assumption on the findings due to a lack of conclusive evidence. This is not conclusive proof of either claim.

ResearchCoord (talk) 21:38, 30 January 2010 (UTC)

A case of list cancer

The list of caffeinated products has been growing steadily, as such lists tend to do. I wonder if anything can be done to impose some sort of discipline on it? Looie496 (talk) 21:12, 7 July 2009 (UTC)

More importantly, the list needs to be checked and referenced... I noticed that the figures for serving size, mg per serving, and mg per litre, did not match up for "Wired X505". But I'm unable to correct without knowing which figures are correct, if any. --Giftiger wunsch (talk) 01:59, 29 July 2009 (UTC)


Please update the references, an article on the new york times should not be referenced as evidence that caffeinated beverages don't cause dehydration. This is just unacceptable.

The article gives three references for that fact, two from scientific publications. The NYT piece is nice because it's highly readable and directly addresses the question. I don't see any harm in pointing readers to it. (Also, it's helpful if you remember to sign your talk page posts by typing ~~~~ at the end.) Regards, Looie496 (talk) 21:05, 18 September 2009 (UTC)
Also, you might be interested in the Talk:Caffeine#Apparent contradiction section above, for prior discussion of this issue. Regards, Looie496 (talk) 21:08, 18 September 2009 (UTC)

How come the full text of reference 46 is in the reference list? Where did it come from? and couldn't simply the references the text cites be referenced directly? Jazzvibes (talk) 12:41, 15 October 2010 (UTC)

That isn't actually a reference, it's an extended footnote. Unfortunately the Wikipedia referencing system makes it very inconvenient to separate footnotes from references. This might actually be better as a subarticle, for the sake of shortening the main article if nothing else. Looie496 (talk) 16:12, 15 October 2010 (UTC)

Does reference number 80 "Rasmussen, JL; Gallino, M (1997). "Effects of caffeine on subjective reports of fatigue and arousal during mentally demanding activities". European Journal of Clinical Pharmacology 37 (1): 61–90. PMID 7794434." exist? The PMID points to a wrong article, I think (well, the author seems to be correct but...). I couldn't find the article from Google Scholar or PubMed or Elsevier (I'm not an expert of searching articles but I think I should have found it with these...). In fact, European Journal of Clinical Pharmacology volume 37 was published in 1989 or something like that. There's something wrong with this reference. —Preceding unsigned comment added by (talk) 11:00, 8 January 2011 (UTC)

It was added here by a user who made a single edit on wikipedia. I could not locate this source by author, title or journal and therefore have removed that addition. Materialscientist (talk) 11:56, 8 January 2011 (UTC)

Effects When Taken in Moderation

The medical diagram shown under "Effects When Taken in Moderation" shows the symptoms and effects of Diabetes, not moderate caffein use. This should be updated or removed, as it may cause those genuinely suffering from undiagnosed diabetes to just quit coffee instead of actually visiting a doctor.

Yeah, that list of side-effects with moderate usage is absolutely incorrect. The reference it cites a) has been removed from Medline and b) looks like it used a "see your doctor if x,y, and z occur" boilerplate that had nothing to do with specific effects of caffeine. I can't find anything in PubMed, Poisoning & Drug Overdose, Drug Monographs, GPNotebook, or Epocrates that would support the image. As noted above, the symptoms noted on the image are more consistent with diabetic ketoacidosis. I'm deleting the image. Blahdenoma (talk) 02:13, 27 April 2011 (UTC)

I think I've figured out what the problem is. See here for discussion. Blahdenoma (talk) 13:38, 29 April 2011 (UTC)

Capacity, capability, and perception

There's an edit war going on as to whether C increases capacity for labor, or just increases the amount you can do before you feel tired without increasing the actual capacity. That's a really interesting question. Of course in order to make the article specific about that, we need reliable sources on it. So in meantime, what we need to do is move the article towards language that states only what we have evidence for, and add as little as possible interpretation on top of the facts. The facts (that we, the editors know about from reliable sources) are the experimental results listed below the passage in question.

The new language about perception was very specific about what leads to the increased performance observed. I don't think we know that, so we certainly shouldn't say that. The old language, "capacity," was a little more vague. I didn't find a precise definition for capacity in this context, so it's open to interpretation, just like the data are. That seems fine to me, but I tried to do a little better, but substituting "capability." I don't think that's a whole lot better, and I encourage others to find wording that might more specifically mean what people are able to do in practice, as opposed to what they might hypothetically be able to do before they collapsed. That could include finding a better word, or writing that idea out in more detail. That's all we can do without more information from reliable sources.

I also encourage finding reliable sources that might enable us to put a more detailed explanation of the experimental observations in. But I think that a detailed explanation without a source should be reverted. Ccrrccrr (talk) 02:16, 2 October 2009 (UTC)

I agree. The main issue is that the phrase you replaced, "increasing the amount mental or physical labor able to be performed before the body perceives itself to be tired", is literally nonsense -- the body does not perceive things. Possibly this was an attempt to state something correct, but how can it be fixed without knowing the source of the information? Looie496 (talk) 04:14, 3 October 2009 (UTC)


This wiki is kind of a mess. Stimulant? In a way. My son has ADHD and after reading texts on alternative treatments (versus prescribed amphetamines like ritalin), which recommended caffeine, we tried coffee (Starbucks) which calmed him down although a second cup put him to sleep. I spoke with his High School Principal who told me of an ADHD student who passed out after two esspressos and had to be carried home. I've known a dozen adults, not on medication, who get sleepy after drinking coffee. The mechanism that caffeine binds and stimulates ATP Cyclase (not neurotransmitter specific), bound to the neuron interior membrane and activated by a neurotransmitter specific protein bound to the exterior of the neural membrane.[1]Hence, activity of all neurotransmitters is increased: GABA, Cholinergic, Nitric Oxide, etc.

'Caffeine resembles strychnine' and 'Caffeine resembles Adenosine' are both rediculous statements with no basis in chemistry. I could get behind alternate activation sites on the receptors like opiates and endorphins or tetrahydrocannabinol and anandamides. Next I'll hear that Barack Obama and Margaret Thatcher look alike?

Nobody noted that caffeine sublimes and that much of the commercially available caffeine comes from the roasting process. Esspresso roasts acually have less caffeine, but oxidation of caffeic acid and tannins create other (quinone)[2] stimulants and unbinds caffeine from tannins. The pKa link goes to an illegible japanese page. pH of 1% solution is 6.9

Laxative? Rem that cocaine was usually cut with "baby laxative" (mannitol), some people equated the strength of the cocaine by how fast they had to use the bathroom. Loperamide and atropine are muscle relaxants and stop diahrea. More likely the tannins and other stomach irritants in Coffee rather than caffeine are responsible.

FYI although arabica was the shade and robusta was the partial shade type, newest ababicas are gene engineered to full sun. Used to be arabica more acid and robusta higher caffeine, but probably no longer.

Caffeine is a vasopressor, causes high blood pressure. If it is a smooth muscle relaxant it makes sense it is a vasodilator. Caffeine is a repiratory stimulant[3]. Cholinergic effects should be noted [4].

Even with references there are so many conflicting studies about the "dangers" and "benefits" of caffeine and coffee. I just came accross one of those stupid "chromosome breakage from caffeine" ones that don't have the scientific methodology of a first grade science project. This is re the section on 'caffeine as insecticide' and 'caffeine as plant inhibitor' sections in the Caffeine wiki. This goes with the 'use coffee grounds as mulch' advice in the 'green' section of the newspaper. Turns out it is the acidic tannins that kill plants and those little black flies that suck roots thrive in that coffee soil. My own Fruit Fly lab experiments and this more recent one[5] seem to debunk the lie that caffeine is bad and should be an insecticide. --Shjacks45 (talk) 19:03, 9 November 2009 (UTC)

With all respect, the foregoing essay is too diffuse to be useful in terms of improving the article. If you see demonstrable errors, could you please point them out one at a time, in a more focused way? Or, if you can back it up with sources, just make the appropriate changes yourself. Regards, Looie496 (talk) 19:12, 9 November 2009 (UTC)

Caffeine and Alzheimer

caffeine You don´t like my edition and my choice of sources . Since I feel it´s both an important and known subject please write about it in a way it suits the science. I can even suggest to be a little milder in your critisizm especially when the general idea behind the particular thought is good. Also - not all people are born in English speaking countries. In my mind it´s a good practice not to delete - edit it yourself in a constructive way instead. Again what is wrong about fhis source [2] Perhaps you may suggest a more adequate source... jmak (talk) 07:40, 23 November 2009 (UTC)

That's a primary research paper. The problem with using sources like that is that on medical topics of broad interest, it is usually possible to find primary research papers to support almost anything. Wikipedia's sourcing rules for medical-related articles (WP:MEDRS) give preference to review papers published in high-quality journals, because good reviews are more likely to give views appropriate weight. In this case, it looks to me like PMID 19230121 is by far the best source right now. I don't know enough about this topic to edit the article myself. Looie496 (talk) 18:34, 23 November 2009 (UTC)

Caffeine and Acetylcholinestarase

Can someone add something on this? and maybe its clinical significance? Reference from here. Andrei A A (talk) 16:33, 8 December 2009 (UTC)

Starbucks info in sidebar

Since I have no idea why we should single out Starbucks caffeine information I deleted it. It falls well within the drip range anyway. RyanEberhart (talk) 21:53, 9 December 2009 (UTC)

Drug interactions

Help I think that a section on drug interactions would be appropriate (e.g. pharmacological lithium), but I'm not sure how this fits into articles about chemistry. I would like to request that this section be added to this article, if anyone has the wherewithal. —Justin (koavf)TCM☯ 00:26, 22 January 2010 (UTC)

Hello. I don't know. Maybe, ff notable, could be integrated into #Metabolism_and_half-life? Twipley (talk) 15:20, 9 February 2010 (UTC)

Please Edit "Coffee and Children" Section.

Please edit the Coffee and Children section as it communicates an opinion and is not supported by conclusive information. Please reference my notes on this topic under the discussion section, disputing the evidence provided in references 104 and 105. I bring three arguments in support of editing this section.

I would suggest that it be changed to indicate that there are claims both for and against, and that conclusive evidence is not yet available. ResearchCoord (talk) 21:53, 30 January 2010 (UTC)

I just looked back at that section. While I agree with you that some of the sources are not very strong, I don't see any sources at all cited to back up the claims you are making, so it's hard to know what to do at this point. Regards, Looie496 (talk) 00:15, 31 January 2010 (UTC)

I have just reverted your edits on this, which won't do even after MaterialScientist reworked them (sorry). You can't use studies of calcium effects in the elderly (especially old, out-of-date studies) to infer effects on children. If you want to claim possible effects on children, you need up-to-date authoritative sources that specifically discuss effects on children. Regards, Looie496 (talk) 16:40, 31 January 2010 (UTC)

Its Effects on Sleep

There was this study not so long ago, published graphs of sleep when caffeine taken around midday, either a placebo, 100, 200, or 300 mg. Effects were drastic. People woke up more often during the night, and had more N2 and less N3 sleep with higher amounts of caffeine taken. REM sleep also almost disappeared (!), compared to staying the normal 20 to 25% for the baseline (placebo) group.

More can be found on Google Scholar for the curious ones. Twipley (talk) 15:14, 9 February 2010 (UTC)


According to the works cited 7, 8 & 9 and stated in the intro caffeine does not cause one to be come dehydrated. There is then an info graph of side effects under the sub topic Caffeine intoxication. In this graph Dehydration is listed as a side effect under systemic effects. I recommend changing it from what it is now to an altered picture that does not have dehydration listed. ( I made the picture and will go ahead in change it in a few days if no one can explain this seeming contradiction. —Preceding unsigned comment added by Arah81 (talkcontribs) 00:04, 14 February 2010 (UTC)

Mode of Action

The article states that it decreases blood flow to the brain and it is unclear how this causes increased alertness.

As far as I'm aware this isn't entirely true:

Caffeine - Mechanism of Action The caffeine molecule is structurally similar to adenosine, and binds to adenosine receptors on the surface of cells without activating them. This effect, called competitive inhibition, interrupts a pathway that normally serves to regulate nerve conduction by suppressing post-synaptic potentials. The result is an increase in the levels of epinephrine (adrenaline) and norepinephrine released from the pituitary gland. Epinephrine, the natural endocrine response to a perceived threat, stimulates the sympathetic nervous system, leading to an increased heart rate, blood pressure and blood flow to muscles, a decreased blood flow to the skin and inner organs and a release of glucose by the liver.

The metabolites of caffeine contribute to caffeine's effects. Theobromine, is a vasodilator that increases the amount of oxygen and nutrient flow to the brain and muscles. Theophylline, the second of the three primary metabolites, acts as a smooth muscle relaxant that chiefly affects bronchioles and acts as a chronotrope and inotrope that increases heart rate and efficiency. The third metabolic derivative, paraxanthine, is responsible for an increase in the lipolysis process, which releases glycerol and fatty acids into the blood to be used as a source of fuel by the muscles (Dews et al. 1984).

I've just copied that from another website, but it's backed up by numerous other sites. Becky kirk43 (talk) 07:36, 30 March 2010 (UTC)


Where is the source for half-life being 4.9 hours? The data I found here says 5.7 hours in healthy adult. --Huggie (talk) 11:57, 3 April 2010 (UTC)

There is also a more recent source that has perhaps more precise data: "The extrapolated elimination half-lives of caffeine in the non-smokers and the smokers were 4.3 +/- 1.5 and 3.0 +/- 0.7 h respectively." --Huggie (talk) 12:02, 3 April 2010 (UTC)

table omission

Please add caffeine content of decaffeinated tea. —Preceding unsigned comment added by Skysong263 (talkcontribs) 17:21, 2 June 2010 (UTC)

Origin of word "Caffeine" ?

Many reputable sources claim that Friedrich Ferdinand Runge (1795-1867), who (partially) isolated caffeine in 1820, coined the word "Kaffein", from which the English word "caffeine" stems.

However, in Runge's article on coffee -- where he detailed his isolation of caffeine, and which appeared in his book Neueste phytochemische Entdeckungen zur Begründung einer wissenschaftlichen Phytochemie [Latest phytochemical discoveries for the founding of a scientific phytochemistry] (Berlin, Germany: G. Reimer, 1820) -- Runge never used the word "Kaffein". Instead, he used the word "Kaffeebase" (an alkaline substance that exists in coffee).

A French chemist who isolated caffeine in 1821 -- Pierre-Jean Robiquet (1780-1840) -- also did not use the word "cafeine" (the French version of "caffeine") in his writings as late as 1823. (See pages 55-56 of his article on coffee ("cafe") -- where he details how he isolated caffeine -- in the Dictionnaire Technologique, ou Nouveau Dictionnaire Universel des Arts et Métiers, ... (Paris, France: Thomine et Fortic, 1823), vol. 4.)

The person who most likely coined the word "cafeine" was Pierre-Joseph Pelletier (1788-1842). In 1817 he had co-discovered emetine. In 1818 he had co-discovered strychnine. In 1819 he had co-discovered brucine. In 1820 he had co-discovered and named quinine. He claimed to have also co-discovered caffeine in 1821 -- although he conceded priority to Robiquet -- and as early as 1822 he was using the word "cafeine" in print: see pages 35-36 in Dictionnaire de Médecine (Paris, France: Béchet Jeune, April 1822), vol. 4.

Thus Pelletier was using the word "caffeine" before either of the two men -- Runge and Robiquet -- who had discovered it before Pelletier.

Cwkmail (talk) 03:07, 20 July 2010 (UTC)

I agree; the current text is incorrect, since Runge uses the term Kafeebase not Kaffein. Also the date of his publication was 1820, not 1819 as was incorrectly stated in the first sentence. I corrected the date; will correct the history of the nomenclature later, if nobody else does first... Gacggt (talk) 15:23, 27 August 2010 (UTC)

Adding (drug) to title.

The article "Cannabis (drug)" has (drug) behind it, which is misleading, because cannabis itself is a plant only. Coffee is also just a plant, but a plant that contain the psychoactive drug Caffeine.

So to the title of this article should be added (drug).

The change of titles will help on the accuracy and objectivity of these articles.

(Pethol (talk) 08:48, 22 August 2010 (UTC)).

The article Cannabis discusses the genus of plants, hence the modifier for a second article. There is no title conflict requiring such a modification.Novangelis (talk) 16:03, 22 August 2010 (UTC)

Friedlieb, not Friedrich

The chemist who first purified caffeine was Friedlieb Runge, not Friedrich Runge. This mistake unfortunately also appears on the chemist's page. Can an administrator please fix that??

Gacggt (talk) 16:51, 27 August 2010 (UTC)

It doesn't take an admin to do that. After verifying from sources that you are correct, I moved the article about him to Friedlieb Ferdinand Runge, and fixed the first sentence. Looie496 (talk) 17:16, 27 August 2010 (UTC)
Okay, thanks very much Gacggt (talk) 20:30, 27 August 2010 (UTC)

Typo in molecule rendering?

I only had a few years of chemistry about 10 years ago, but isn't there a typo in the (vastly popular) image of the caffeine molecule? The Nitrogen atom with a double covalent bond is attached to a Carbon that only has 3 connections. So either there's an extra electron floating about that Carbon, or there a missing H next to it. Is that a common notation pattern (such as leaving off the C for Carbon atoms in rings)? Mangler (talk) 14:30, 17 September 2010 (UTC)

It is just notation. You can see the unrendered hydrogen in the 3D "ball and stick" model to the right.Novangelis (talk) 14:56, 17 September 2010 (UTC)
"Implicit H on C" is one of the standard features of a skeletal formula diagram. DMacks (talk) 16:09, 17 September 2010 (UTC)

Analgesic effects of caffeine

Hey guys the article states "Caffeine also increases the effectiveness of some drugs. Caffeine makes pain relievers 40% more effective in relieving headaches and helps the body absorb headache medications more quickly, bringing faster relief.[87]"

The reference provided is to a website called webMD, which itself has no references and is hardly a reputable source. I think the above statement is misleading and intended as an advertisement for combination paracetamol & caffeine drugs. The statement suggests that it makes the analgesic work better and be absorbed better, when in actual fact it is most likely the caffeine which is providing the extra analgesic affect (independently of the paracetamol). Some studies have found caffeine alone to be as effective as paracetamol alone for relief of headaches. Also, a study in rats showed caffeine inhibits gastric emptying and impairs absorbtion of paracetamol (

I think this could be expanded to highlight the actual effect of caffeine as an analgesic rather than supposedly increasing the effectiveness of other drugs (I can't find any evidence for this). (talk) 04:42, 1 October 2010 (UTC)

I remember being allowed to use web md (but not wikipedia) for a high school research paper, but yeah, an actual study would be nice.Gniob (talk) 18:34, 28 July 2011 (UTC)

External Links

This article has a long list of external links. Per WP:EL I think a large number of the links in this article are not appropriate. In particular, under the heading "Links normally to be avoided" is the text: 1. Any site that does not provide a unique resource beyond what the article would contain if it became a featured article. -- I think this applies to some of the links here and thus I am removing them. I am giving justification here because I may end up removing a large number of them. Cazort (talk) 16:18, 8 October 2010 (UTC)


The section on obscure religious references seems out of place in this article. If it were major restrictions on major religions, perhaps, but the ones listed currently are not noteworthy. I've removed the section (or rather commented it out). Anthiety (talk) 04:31, 22 October 2010 (UTC)

I don't agree that the ones listed are not noteworthy, but I won't myself undo the edit. Looie496 (talk) 04:42, 22 October 2010 (UTC)
I also think that the section was noteworthy. Islam is a major religion, and the acceptance of coffee within it only occurred after a lot of debate. As for the others, I would consider not consuming it a major restriction. ~rezecib (talk) 04:50, 22 October 2010 (UTC)

Merge Pharmacology with Health effects of Caffeine

There's a new article (Health effects of caffeine) with the same scope as Caffeine#Pharmacology. I'm thinking of starting a merge discussion, but would like to see if anyone else thinks merging might be a good idea, first. ~rezecib (talk) 19:39, 8 November 2010 (UTC)


I'm just thinking that we could possibly have a section (more than what there currently is), or even and article on caffeine addiction, overuse, withdrawal, etc.; something that is seemingly becoming more prominent in society today, or even an article on it's social / recreational use (this article is heavy on the pharamacology [quite rightly], although it also has a good history section). Just throwing ideas out there. I might start something myself, if I don't get any objection. - (talk) 08:49, 3 December 2010 (UTC)

Sounds reasonable, but it might be good to discuss your changes more specifically here first. Since this is a Featured Article, the level of oversight of edits will be pretty high. Looie496 (talk) 17:26, 3 December 2010 (UTC)

Error in quantities?

The section on tolerance says that tolerance occurs "after consuming 400 mg of caffeine 3 times a day for 7 days". But in the section on caffeine intoxication, it says that acute overdose occurs over 300 milligrams. Isn't there something wrong here? Pacolaro (talk) 01:20, 8 December 2010 (UTC)

Alertness benefits questionable

The introductory section of the article says:

"In humans, caffeine acts as a central nervous system (CNS) stimulant, temporarily warding off drowsiness and restoring alertness."

This is conflict with which states for example

"A recent large study strongly supports the evidence against any true cognitive or alertness benefit for caffeine."

--Skarkkai (talk) 16:32, 8 January 2011 (UTC)

Regarding the use of the word "whence" in the first paragraph.

I'm a complete noob when it comes to editing, so this message might sound extremely ill-conceived. However, when reading the article, it occurred to me that I'd never seen "whence" used in such a context, and submit that I believed it to be an error, when the word intended was "hence". I realise that this must be a heavily-watched page and that a grammatical error therefore is entirely unlikely, but I'd rather err on the side of caution. (talk) 14:22, 12 January 2011 (UTC)

That does seem like an un-necessary use of an uncommon word. I changed it a bit.DMacks (talk) 15:23, 12 January 2011 (UTC)

Caffeine & ADHD Focusing

Sources for Caffeine as a stimulate for ADHD focusing: (Slides 22-24) Personal Experiences: I have Adult ADHD at age of 24 and I find Caffeine makes a big different when needing to focus. If I'm doing a task or anything and become stuck due to a lack of stimulation Caffeine is a great way to fill the gap which allows the continuation of the task. Improvements for ADHD is already mentioned "In essence, caffeine consumption increases mental performance related to focused thought while it may decrease broad-range thinking abilities." but not linked to ADHD in the statement. —Preceding unsigned comment added by (talk) 10:49, 30 January 2011 (UTC)

Welcome to Wikipedia and thank your for your comments on the article! However, as mentioned by Cresix on the ADHD talk page, the sources you have provided here are not reliable sources because they are self-published or loop back citations to Wikipedia. Your personal experiences are fascinating, however content published on wikipedia must be verifiable and cannot be based on original research. –TheIguana (talk) 18:58, 30 January 2011 (UTC)

Effect on teeth?

The effect of caffeine on teeth is very well documented. Perhaps someone could add a section about it? (talk) 14:32, 5 March 2011 (UTC)

Well, that someone could be you, presuming that the effect is documented in sources that meet our criteria as spelled out in WP:RS. Looie496 (talk) 17:18, 5 March 2011 (UTC)

If you're talking about stained teeth, that's caused by non-caffeine pigments in tea and coffee.Gniob (talk) 18:37, 28 July 2011 (UTC)

Undue weight?

It seems that in some sections (psychological effects, Caffeine Toxicity), this article is written heavily biased to the negative health effects of Caffeine. For instance: the toxicity section makes reference to "with serious symptoms of overdose requiring hospitalization occurring from as little as 2 grams of caffeine"... an unusual claim, due to the fact that the highest estimated portion of the LD50 of caffeine to be 100mg/kg. At 2 grams: 2000mg/100mg = 20kg person, for this claim to have any real merit. Maybe this 45 pound individual did go to the hospital... but in nowhere near the danger that the writer is suggesting. Also, certain positive effects are tagged as being unsourced, when quick google scholar searches returns three affirmative hits out of the first four results. I think close attention to undue weight should be examined here. Taintedstreetlight (talk) 19:49, 16 December 2012 (UTC)

LD50 is the amount that half of people would die. It is reasonable to believe that amounts less than that can still have serious side effects (although they might not be life threatening)HouseJoffrey (talk) 16:58, 24 May 2013 (UTC)

"Synthesis and Properties" section

Material that was previously in a footnote -- specifically, historical information about the controversy over who had priority in the isolation of caffeine (Runge vs. Robiquet vs. Pelletier and Caventou) --has been moved into the body of the article in its "Synthesis and Properties" section.

Frankly, although I was the author of that footnote, I truly believe that it does not belong in the body of the article. It concerns a historical detail that would not interest the general reader; similarly the evidence presented -- the quotes in foreign languages with translations -- would also not be of interest to the general reader. I would therefore suggest that a "Notes" or "Footnotes" section be created for the the article and that my research be moved there.

Cwkmail (talk) 22:10, 14 March 2011 (UTC)

Use as a phosphodiesterase inhibitor in Saccharomyces research

I deleted the following blurb:

Caffeine is also added to agar, which partially inhibits the growth of Saccharomyces cerevisiae by inhibiting cyclic AMP phosphodiesterase.[6]

For a couple of reasons: 1. It didn't add anything useful the paragraph it was attached to, and seemed out-of-place. 2. The research article cited as a reference only showed that caffeine inhibited the growth of a particular mutant strain of Saccharomyces cerevisiae, and thus I don't think it qualifies as a bit of data that is relevant and/or useful for the average seeker-of-information about caffeine.

If someone wants to start an article on nat3 and nat3 knockout yeast, the deleted blurb would be relevant. Blahdenoma (talk) 01:06, 27 April 2011 (UTC)


Featured articles are to be supported by high quality evidence typically in the form of review articles. This article is not and thus is at risk of losing its FA status. Not sure how many wish to work up upgrading but I will have a go... Doc James (talk · contribs · email) 01:21, 18 May 2011 (UTC)

Let me note that this article is actively maintained by a number of editors. It is only partly medical-related and therefore should only partly be governed by MEDRS. I'm certainly not claiming that nothing here is capable of improvement -- but I believe that most of the content of this article has been pretty thoroughly hashed over at one time or another. Regards, Looie496 (talk) 02:13, 18 May 2011 (UTC)
All the health claims that this article contains should be supported by review articles which at this point in time they are not. Doc James (talk · contribs · email) 08:16, 18 May 2011 (UTC)

Not a Stimulant

Or is it just me? From my earliest age, my parents would give me bottles with coffee in them, because caffeine made me tired. Without it i had (and still have) this tendency to stay awake ridiculous amounts of time before realising it -- which tends to only happen when my eyes are tired enough to dizzy everything.

I mean..I know why everyone says they drink this stuff. But its really hard for me to believe, because its *extremely* tiring even in moderate amounts for me. Whats up with that? x_x (talk) 00:37, 5 June 2011 (UTC)

I just wanted to add that when i was little my parents somtimes would give me maté in the bottle to help me settle down to sleep. Also, for some reason i hate coffee, yet i love Coke... --TiagoTiago (talk) 21:51, 24 July 2012 (UTC)
Personal anecdotes are not really useful here, I'm afraid. This page is for discussion of ways to improve the article, and any improvements must be justified by published literature. Looie496 (talk) 01:34, 5 June 2011 (UTC)

Some people seem to be immune to caffeine, which the article does not mention. It has no effect on me, and I've run into other people who say the same thing. I don't know if there is any published material on this. WilliamSommerwerck (talk) 20:28, 9 November 2011 (UTC)

The article does mention potential resistance to caffeine's effects, which (in large degrees) implies de facto "immunity." Your body metabolizes caffeine, but the effects are likely so minor that you don't notice them. That doesn't mean that caffeine has no effect, simply that you haven't ingested a large enough dose. It's unlikely that caffeine was responsible for OP's fatigue, given what we know of it's biochemical function. Biochemgeek (talk) 11:46, 2 November 2012 (UTC)

It is a stumulant because it causes a higher production of dopamine. Low levels of dopamine is linked to hyperactivity and restlessness. My theory is that if your body, as a child, had trouble regulating dopamine (like a body that is not fully developed may do) then it might have led to your hyperactivity. When given small amounts of caffiene, one could assume your hyperactivity may have been suppressed, allowing you to do what healthy kids normally do... sleep nearly half the day away. This would have the opposite effect on you as your body began to fully mature. (talk) 14:45, 2 November 2012 (UTC)

Sorry to bring this topic of conversation back, but at University studying Psychology, when we covered Drugs we were told quite specifically that caffeine (as a drug) is not a stimulant, but does end up having a stimulating effect. That is to say that the Caffeine blocks adenosine receptors, which prevents your body from recognising a decrease in energy, but also causes your body to produce adrenaline as a response. explains this in more detail. Just wondered if someone more in the know could clarify the situation and suggest whether or not we need to re-word this section? AnthonyW90 (talk) 10:57, 18 March 2013 (UTC)

"Stimulants (also referred to as psychostimulants) are psychoactive drugs which induce temporary improvements in either mental or physical function or both. Examples of these kinds of effects may include enhanced alertness, wakefulness, and locomotion, among others." Caffeine is a stimulant. Not a direct catecholaminergic stimulant, but a stimulant nonetheless. Exercisephys (talk) 12:55, 18 March 2013 (UTC)

Caffeine and ADHD

I just added a segment about caffeine's effects on ADHD. The claims are well-sourced and verifiable, and I think it will answer a lot of the questions people have posted in the talk page. --SuperEditor (talk) 18:54, 15 June 2011 (UTC)

Structural comparison to adenosine

The "Mechanism of action" section contains File:Caffeine and adenosine.svg to illustrate the structural relationship between these two chemicals. However, the adenine rings are not oriented the same way. Should one of those structures be flipped vertically so that the 6-membered rings have their two nitrogen atoms and an exocyclic electronegative atom in the same positions? DMacks (talk) 01:30, 13 July 2011 (UTC)

Chocolate does no have caffeine

Chocolate does not have caffeine but has another substance called Theobromine which is similar to caffeine. › Urban Legends › Food — Preceding unsigned comment added by (talk) 23:21, 30 August 2011 (UTC)

Interestingly, our wikipedia article provides multiple references including published specific analysis, supporting that there is caffeine present. Can't be an "urban rumor" if there is actual scientific evidence (however, it's known to be low and variable level). DMacks (talk) 01:34, 31 August 2011 (UTC)


There is so much primary research here when there are lots of review articles to base the content on. Definitely in need of an update.Doc James (talk · contribs · email) 07:16, 23 September 2011 (UTC)

Unable to find evidence to back this up from good sources

===In children===

Excessive intake of caffeine does not result in stunted growth.[unable 1] Children are found to experience the same effects from caffeine as adults.

However, subsidiary beverages that contain caffeine, such as energy drinks, most of which contain high amounts of caffeine, have been banned in many schools throughout the world, due to other adverse effects having been observed in prolonged consumption of caffeine.[unable 2] In one study, caffeinated cola has been linked to hyperactivity in children.[unable 3]

Doc James (talk · contribs · email) 09:02, 23 September 2011 (UTC)

  1. ^ "Fact or fiction: Common diet myths dispelled". MSNBC. 2006. Retrieved 2009-08-03.  Unknown parameter |month= ignored (help)
  2. ^ "Caffeine and Your Child". KidsHealth. 2005. Retrieved 2009-08-03.  Unknown parameter |month= ignored (help)
  3. ^ "Caffeinated Cola Makes Kids Hyperactive". WebMD. 2005. Retrieved 2010-02-05.  Unknown parameter |month= ignored (help)
This extensive article does not comment on it at all [3] I did find a book that commented on it and thus added a line.Doc James (talk · contribs · email) 09:19, 23 September 2011 (UTC)


That huge chembox at the top really messes up the layout of the article. What do you think about moving it, or at least a lot of the details, into the body of the article? Looie496 (talk) 18:56, 23 September 2011 (UTC)

Actually the chembox documentation suggests that the right solution to situations like this is to create a subpage called caffeine (data page), and move some of the information into it. Looie496 (talk) 19:11, 23 September 2011 (UTC)
What you did here is certainly not an improvement of the article. While some information might be removed and put on a data page, this is certainly not the case for central information such as the CAS RN, density or the pKa. Further more, there is certainly no need to hurry that you cannot wait for answers. I restored the chembox for the discussion. --Leyo 07:27, 24 September 2011 (UTC)
No information was moved. The box was just split with the chemical details moved to that section. What we ended up with is duplication of a bunch of content in the article. Doc James (talk · contribs · email) 08:10, 24 September 2011 (UTC)
Could you please show me other examples, where the chembox is split in a similar way? --Leyo 08:30, 24 September 2011 (UTC)
Yes I am undecided if this is what we should do. Having so much detail in the lead though and this pushing down the images that are in the sections of the body of the article is poor formating. What we do not need however is two copies of all the chemical content in the article.Doc James (talk · contribs · email) 09:05, 24 September 2011 (UTC)
The latter was not intended. I seem to have lost track due to the numerous small edits in the history. --Leyo 09:10, 24 September 2011 (UTC)
Let me say that it's clear to me that what I did is imperfect. I have learned in my time editing Wikipedia that when facing a problem, the first necessity is to do something, otherwise discussion ends with nothing happening. But I am absolutely open to alternative solutions. What I am not really open to is having that ridiculously large chembox sit at the top of the article indefinitely. The bulk of what is there is not critical information for the average reader; it does not belong at the top of the article. Looie496 (talk) 13:29, 24 September 2011 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── Why not put a {{drugbox}} at the top? (see example to the right) Boghog (talk) 14:01, 24 September 2011 (UTC)

That is a great idea. More clinical info. Doc James (talk · contribs · email) 14:31, 24 September 2011 (UTC)
Excellent -- the perfect solution! Looie496 (talk) 14:50, 24 September 2011 (UTC)


Something has to be done about the Chemistry section -- the graphics are overflowing the section massively. Would it make sense to create a subarticle titled perhaps Chemistry of caffeine, and move most of the graphics there, as well as some technical information? Looie496 (talk) 16:37, 25 September 2011 (UTC)

Didn't we agree that we won't split an infobox into two infoboxes some time back? --Rifleman 82 (talk) 16:54, 25 September 2011 (UTC)

That issue no longer exists -- the article now has a drugbox at the top and a chembox in the Chemistry section. Looie496 (talk) 17:11, 25 September 2011 (UTC)
The text in the chemistry section is relatively short and in my opinion it should be expanded somewhat. This in part would solve the problem of the graphics overflow. Caffeine after all is a chemical. A basic requirement for featured article status is comprehensiveness and there is no way an article about caffeine can be comprehensive without a chemistry section. The other part of the problem is that we still have a very large chembox. I also agree that we should not split the infoboxes. The ultimately the best solution in my mind is to merge the {{drugbox}} into the {{chembox}} as proposed here and make many of the sections optionally collapsible. If we had such a box with many of the chemistry specific sections collapsed, the merged box would not overwhelm the lead and the chemistry section would be much less cluttered. Boghog (talk) 17:18, 25 September 2011 (UTC)
I'd agree with Boghog, that the chemistry section is actually quite short compared with the drug aspects of caffeine. I don't see how it might be helpful to split the chemistry off into a separate article. If anything needs to be hidden, it would be the relatively long list of identifiers (but this is not peculiar to this compound). I'd actually trim some of the comments about caffeine - mp, sol., pKb, as they are already in the chembox and they are not really surprising, and they don't deserve much elaboration. Let me see what I can find about it, thought I imagine that involves adding an image of a purely chemical synthesis. Perhaps a section history - how its structure was illucidated, maybe involving comparing a chemical synthesized sample vs. natural product extract. That said, I don't recall that this synthesis is of particular importance though, because decaffeination of coffee probably is the major source of the purified compound.
As a chemical, I think this section (analogous to structure & properties, and synthesis/biosynthesis) should be higher up in the article. It makes no sense of talking about what it does until you define what it is, and how you can make it/get it. --Rifleman 82 (talk) 18:17, 25 September 2011 (UTC)
I don't think we should regard the order of sections as set in stone -- but we should bear in mind that this is a very popular article, with over 5000 page views per day, and the great majority of readers are probably more interested in the drug properties than the chemical properties. Looie496 (talk) 18:26, 25 September 2011 (UTC)
My personal preference is the same as Rifleman, chemistry should be moved up, but Looie does have a valid point. Most readers are probably more interested in drugs than chemicals. Concerning the chemistry text, I added what I thought were the most fundamental properties of practical interest, water solubility and pKa. Melting point and solubility in ethanol are less important. I could be wrong, but I don't think the first structure determination was confirmed by independent chemical synthesis, the chemical synthesis appears to have come much later. I was prompted to put it in based on the pre-existing text which mentioned the chemical synthesis starting from dimethylurea and malonic acid which seemed a little odd. Digging around confirmed that the pre-existing text is reasonable and I thought the best way to support the existing text was to add a synthesis schematic. Furthermore I thought the chemical synthesis offers an interesting contrast to the biosynthesis. Boghog (talk) 18:50, 25 September 2011 (UTC)
OK, here is what appears to be the first chemical synthesis of caffeine: Fischer, Emil (1895). "Neue Synthese der Harnsäure und ihrer Methylderivate". Berichte der Deutschen Chemischen Gesellschaft. 28 (3): 2473–2480. doi:10.1002/cber.18950280329.  Unknown parameter |coauthors= ignored (|author= suggested) (help) Boghog (talk) 19:25, 25 September 2011 (UTC)
Thanks. How's your German? I looked through the article briefly, and I think I know what he did. However, I didn't notice him claiming the first synthesis of caffeine, or of caffeine even being the focus of the article. --Rifleman 82 (talk) 20:47, 25 September 2011 (UTC)
My German is rusty, but I will try to slog through it. The main purpose of the article was to prove the structures various xanthine derivatives including caffeine, but not specifically to provide a synthesis of caffeine. Furthermore Fischer did not claim to be the first. Nevertheless according to the Merck Index this does appear to be the first reported synthesis of caffeine. Boghog (talk) 03:46, 26 September 2011 (UTC)

Where'd the picture of dry anhydrous caffeine go? We usually have pictures of the pure compound in the box, preferably anhydrous. Pictures of solutions, or other crude extracts are left in the text. The picture at the top is a cup of coffee, not a sample of caffeine. --Rifleman 82 (talk) 20:41, 25 September 2011 (UTC)

It got lost in the shuffle between different types of infoboxes. Let me note that it's a pretty sucky picture. Looie496 (talk) 20:48, 25 September 2011 (UTC)
I'll go put it back. It's functional; shows the compound as what it is, a white crystalline solid. It's not grainy, though the lighting is not the best. That's better than many pictures on WP. It's probably unrealistic to expect pictures of all compounds to be professionally photographed. --Rifleman 82 (talk) 20:53, 25 September 2011 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── I created a prototype {{chembox Drug‎}} template, merged (almost) all the data from the two infoboxes into this single template and placed it at the top. In its default collapsed state, it is about as long as the original drugbox, but it contains essential all of the information that was contained in the chembox + drugbox templates. Please note that to create this template, I merged code from the chembox into the drugbox, but long term the merger should be done in the other direction. Hence I would like to stress that this template was created only to illustrate what a merged template might look like and to help this article pass the featured article review. Boghog (talk) 21:25, 26 September 2011 (UTC)

Well, it's certainly a move in the right direction. Looie496 (talk) 22:08, 26 September 2011 (UTC)

Thanks for your efforts. A few comments: CAS should link out to Commons Chemistry, which is an authoritative source for CAS numbers; NIH is not an authoritative source. The formula should not be hidden. There may be many identifiers, but this one should not be hidden. I think the physical appearance should not be hidden either. Identifiers should be collapsible, though, because it is a list of numbers which don't mean much to someone who doesn't know what to do with it. --Rifleman 82 (talk) 00:05, 27 September 2011 (UTC)

Thanks for your feedback. I have changed the CAS link from NIH to ACS. For now I have uncollapsed the chemical properties section that contains the formula. Perhaps there should be a new "vital stats" section containing the IUPAC name, formula, MW, and physical appearance, but I am not sure what to call it. I am also not sure I agree that the identifier section should collapsed since it contains a large number of useful externals links where the reader can find more detailed information about caffeine. Boghog (talk) 06:25, 27 September 2011 (UTC)

I think having a "vital stats" section would be helpful. We had that in the old chembox, but it was taken out of the new chembox perhaps on the assumption that the properties and identifiers sections would not be collapsed. --Rifleman 82 (talk) 15:12, 27 September 2011 (UTC)


I am not sure why physical effects where split off from health effects? And we ended up with two sections on psychology? Physical effects are health effects.Doc James (talk · contribs · email) 05:15, 26 September 2011 (UTC)

I split it off because it doesn't seem to make sense to me to refer to the basic stimulating properties of caffeine -- the main reasons why people use it -- as health effects. When I drink my morning cup of coffee, I don't do it for my health. Looie496 (talk) 06:06, 26 September 2011 (UTC)
Any effect on the health is a "Health effect". I drink coffee all day long for the stimulating properties and view this as a health effect :-) Doc James (talk · contribs · email) 06:25, 26 September 2011 (UTC)
My impression is that yours is an unconventional view. If somebody asks me "does caffeine affect my health?", and I say, "yes, it makes me more alert", I think I'll usually get a puzzled look or a laugh. I fear that putting things that way will impair our ability to communicate with ordinary readers, who won't understand what we are saying. Any third opinions on this point? Looie496 (talk) 14:52, 26 September 2011 (UTC)

And mine is that your view is unconventional :-) There is that psychological phenomena where people think that their own view is the majority... I guess we could ask for greater input. I prefer less main heading to more as it keeps the TOC short. BTW I think this article has really improved over the last week. My concerns regarding sourcing of the health care content have been addressed. Doc James (talk · contribs · email) 12:47, 27 September 2011 (UTC)

Merge Health effects of caffeine

Now that we have updated this page. The subpage "health effects of caffeine" is little more than a poorly referenced subpage using both a great deal of primary research and old studies. Wondering if we should merge it here? Doc James (talk · contribs · email) 05:18, 26 September 2011 (UTC)

I'm not opposed as long as material isn't merged in a way that makes it more difficult for this article to pass the FAR. Looie496 (talk) 14:54, 26 September 2011 (UTC)
Agree. --Doc James (talk · contribs · email) 12:50, 27 September 2011 (UTC)
Agree. EEG test would require you to cease any intake of caffeine, for a some days at least(though the half life is much less than that). Electrical Activities are different of the two brains. atleast when you see for yourself the activities with alpha and theta waves. ;) Rmraihan (talk) 14:41, 3 November 2012 (UTC)

As there's been no movement on this for two years, and it appears that the sources have to some extent improves, and given the length of the article Health effects of caffeine, I have removed the merge tags. LT90001 (talk) 12:07, 11 October 2013 (UTC)


I think the article is missing a discussion of the interactions between caffeine and alcohol. There is plenty of literature on the topic, but surprisingly it is difficult to come up with good recent review papers. The best sources I can find are this Neuropsychopharmacology paper and this review of energy drinks. The first is a primary source per MEDRS, but has a pretty nice review in its introduction, and the journal is very reputable. Any thoughts on alternatives? Looie496 (talk) 22:31, 27 September 2011 (UTC)

I disagree that any conversation should be extensive. A reference to alcohol under Health Effects would be pertinent, and should link to a separate page (Caffeine and Alcohol should be an independent article, given the extensive literature). Surprisingly, I can't seem to find much on this either. Biochemgeek ([User talk:Biochemgeek|talk]) 11:50, 2 November 2012 (UTC)

In other animals

Human are animals thus we state in other animals per WP:MEDMOS Doc James (talk · contribs · email) 01:16, 28 September 2011 (UTC)

Agree, especially because here we appear to be making the distinction between general effects that apply to humans and maybe also animals vs those that are specific or different for non-humans. It was even previously discussed here a few years ago (Talk:Caffeine/Archive 4#Anthropocentrism) and definitely did not have consensus to remove it (as an involved, I don't want to make an analysis of whether consensus actually explicitly supported keeping it). DMacks (talk) 01:36, 28 September 2011 (UTC)

The basic definition of animal includes "any such living thing other than a human being." and "Any non-human animal, esp. a land-living mammal", those are dictionary definitions, but another definition is "A living organism characterized by voluntary movement". I never considered humans part of the animal kingdom, which is why I thought it wasn't in the right context, putting humans in the same category as animals, which seems odd calling it a distinction from a different point of view. Anyway, just thought I'd comment. Editor182 (talk) 02:04, 28 September 2011 (UTC)

This is always a challenge because any way of handling it feels wrong to a large group of readers, but we've developed a standard way of handling it, and we might as well stick to it. Looie496 (talk) 03:05, 28 September 2011 (UTC)
Have always considered humans a type of animal. This is how they are seen medically anyway. Doc James (talk · contribs · email) 03:22, 28 September 2011 (UTC)

'Dogs' needs to be removed as an example of an animal in which caffeine has 'considerable toxicity,' not only because there is little evidence in general to back up this claim, but also because the article that statement links to in its citation is not credible (full of hearsay and pseudoscience). — Preceding unsigned comment added by Alecmwatson (talkcontribs) 05:40, 14 March 2012 (UTC)

I agree the article has no citations and seems unscientific, this r/ask-science question mentions this pdf which seems to be a better bet. Since this document references other sources it may be better to reference those directly. Kosievdmerwe (talk) 22:33, 1 October 2012 (UTC)

"While safe in humans (...) toxic to various animals (...)". The source about dogs cites 150mg per kg body weight as lethal for dogs, which corresponds to a toxic dose for a 70 kg human as high as 10.5 gramms. This 10.5g is pretty much exactly the LD50 dose for humans. Caffeine seems to be as toxic for humans as it is for dogs. Animals suffer at smaller doses just because of their lower body weight, but the sentence conveys the impression of a physiological difference between humans and dogs, which can't be endorsed by their identical lethal doses per kg. Just like claiming "water is safe for humans but lethal for mice", because the harmless amount of 2 liters of water per day for a human would kill every mouse by overstraining her digestive system if not make it explode. — Preceding unsigned comment added by (talk) 04:53, 30 April 2012 (UTC)

Society and culture

We discuss some of the religious issues but what about the rest of the society and cultural significance?--Doc James (talk · contribs · email) 13:40, 1 October 2011 (UTC)

Merge Health effects of caffeine to caffeine

All the important details are covered in the main article and to a better extent. We have subarticles that deal with the individual topics such as intoxication. Thus I propose we merge what is good here.--Doc James (talk · contribs · email) 14:03, 5 October 2011 (UTC)

Phosphodiesterase inhibitor mechanism

Why does this article have nothing on caffeine being a cAMP diphosdiesterase inhibitor, leading to increasing levels of cAMP leading to increased neurotransmitter release and neuronal function? That is just as important as blocking adenosine receptors IMO. — Preceding unsigned comment added by (talk) 23:06, 7 November 2011 (UTC)

Can you cite any literature to back that up? Looie496 (talk) 23:14, 7 November 2011 (UTC)

(outdent) I added about inhibition of phosphodiesterase; I have not expanded to say about the knock on effect on cAMP and neurotransmitters. That is for someone else to do. :) Or maybe I will do it when I have the time,,, sometime. :-P--Literaturegeek | T@1k? 16:12, 17 April 2012 (UTC)


Add a controversy section-- (talk) 21:29, 21 November 2011 (UTC)

Which controversy do you refer too?--Doc James (talk · contribs · email) 07:01, 22 November 2011 (UTC)

Does caffeine stunt growth

I have read that it may or may not stunt growth> — Preceding unsigned comment added by Bacon467 (talkcontribs) 03:39, 30 November 2011 (UTC)

Edit request on 17 August 2012

the diagram structure of the caffeine is wrong, it is missing a hydrogen on the furthest left carbon (not illustrated as a carbon, but as a double bond and a single bond) this is a chemically wrong structure as the carbon is clearly missing a bond, it must have 4 not three as is shown. this structure does not correlate with the other information given in the page such as the chemicat formula (C8H10N4O2) and the IUPAC name. I would be appreciative if this was changed so as to avoid any confusion. (talk) 12:19, 17 August 2012 (UTC)

The chemical structure is correct - see skeletal formula for an explanation for why not all atoms are drawn explicitly. However, the diagram that was in the article is somewhat confusing because it is a mix of chemical drawing styles, so I have switched it with one that is drawn in a consistent style. Hopefully this will avoid this type of confusion in the future. ChemNerd (talk) 13:41, 17 August 2012 (UTC)
Your explanation does not directly address the question. Both structures are correctly drawn. The original structure has only one implicit hydrogen atom whereas the new structure, implicit hydrogen atoms are used consistently throughout. The disadvantage of the new structure is that it is inconsistent with other structure diagrams elsewhere in this article. Boghog (talk) 15:06, 17 August 2012 (UTC)
Hmmm, I hadn't considered consistency with other diagrams in the article. I think it would be greatly preferable if all the drawings used a style in which all the hydrogen and carbon atoms were depicted consistently (as in File:Caffeine-2D-skeletal.svg, "new"), but it's probably not worth the effort to redraw them all. So if you would like to revert to the original, I won't object. ChemNerd (talk) 16:44, 17 August 2012 (UTC)

Poorly worded sentence

"Caffeine is toxic at sufficiently high doses. Ordinary consumption can have low health risks, even when carried on for years"

This doesn't read correctly. If the point is to emphasise that the risk is low then it should read, for example, "Ordinary consumption has low health risks, even when carried on for years". If the point is to emphasise that some risk does exist then it should read, for example, "Ordinary consumption can have low health risks, especially when carried on for years". At the moment it is an inconsistent mixture of the two.

Update Reference

Reference [153] currently points to the wrong url, should be updated to 2001:4479:3A06:83DA:D0C6:D602:DA44:8325 (talk) 07:00, 20 October 2012 (UTC)

Not done: The current URL supports the quote in the article. RudolfRed (talk) 02:52, 21 October 2012 (UTC)

My mistake. I couldn't find the quote on the linked page when I looked for it. Thanks for answering. 2001:4479:3A06:83DA:D0C6:D602:DA44:8325 (talk) 08:19, 21 October 2012 (UTC) — Preceding unsigned comment added by (talk)

Religion Section the context about Islam

Verbose exchange moved to Talk:Rmraihan/Islam_and_Caffeine. Your concerns are welcome here, but the dialog needs to be conducted with and at less volume.

The main point I would emphasize is that you can't make demands of other Wikipedia editors based on their knowledge or lack of knowledge of Sharia law. That amounts to an appeal to authority (relative expertise of Wikipedia contributors) and is not permitted under the Wikipedia editing guidelines. If you have sources for your claims, please post them here so we can have a calm discussion of their stature and significance.

From what I can find, many Muslims not only consume coffee, but also consume chocolate (which is definitely a stimulant in the mind of most food chemists). Many food chemists regard sucrose (table sugar) as a stimulant. In my own opinion, there's no hard and fast way to divide the world of food into stimulants and non-stimulants. Food is chemistry. The closer we look, the more compounds we find in ordinary food, many of which could prove to have stimulatory effects in larger doses. Many people consider MSG to be a nervous system stimulant, and this occurs naturally in a wide range of foods. The main difference with caffeine is that people commonly consume caffeine for the purpose of enjoying its stimulatory effects while few engage in stimulatory thought-crime in their pursuit of MSG. When it becomes less about the food or the chemistry and more about attitude it's far too subjective to debate here.

What could be added to this article are statements to the effect that under some Muslim traditions (which?) caffeine is construed as a stimulant (along with the related compounds theobromine and theophylline?) and that under some Muslim traditions (which? if not exactly the same) no quantity of a stimulant is acceptable (according to what Muslim authority?).

Effects of theophylline from tea: increasing heart rate, increasing blood pressure, increasing renal blood flow. How is that not a stimulant? This is not a matter for Wikipedia editors to debate. For this reason, if the authority doesn't spell out specific items, I doubt the source is workable here. Please provide sources where Muslim authorities spell out specific prohibitions so we don't have to guess at the dividing line between coffee, tea, and chocolate. — MaxEnt 18:32, 30 October 2012 (UTC)

Would you consider taking a look at the edits that were made to the last paragraph of the article over the course of that discussion? Looie496 (talk) 23:38, 30 October 2012 (UTC)

Do you not know "which is metabolised in the liver into 10% theobromine, 4% theophylline, and 80% paraxanthine" ?? I see a neurologist (or troll) here. Why did you throw such a "confusing the general public" paragraph at me? "stimulatory thought-crime" ?? First I'd like to state this MaxEnt guy is putting words into my mouth. This conversation was never about "stimulatory" effects of food. You first summarize me, altering whatever you wish from their. Then deduce that summarization. If you want to deduce something. or logically advance from an argument. advance from MY argument. NOT YOUR made-up argument. As for the Coffee-tea-chocolate, I have already cleared myself up. Secondly, This argument was never about "Stimulating" "foods" it was from the beginning about "Psychoactive" "Drugs". If you do have problems with my definitions, Im afraid, Sir, Either you are intentionally trolling, or have some disabling problems that make you unable to understand science. This article itself clearly states what Caffeine is. It even makes disputes about its legality. Maybe not for your imaginary "religious-sensual" sense, but even for the "well-being" of people. Can you point me to an article, in ALL of internet and ACADEMICS that states Sucrose is a Psychoactive Drug?? Why would you mix things like this and throw a question like this? Do you not understand what a psychoactive drug is? or do you refuse to do so? This is not a humanities article, if you want to continue further. Read science. this is not about what people or cooks think about food. If you do believe there is an issue with stimulants-psychoactive drugs ANY MORE. then ressist your urge to post ANY MORE REPLIES further.NO MORE TROLLING. And lastly, as a favor from me, I'd like to tell you a bit about MSG. DO NOT MIX NATURAL GLUTAMATES THAT OCCUR IN FOOD AND ARTIFICIAL MSG. artificial msg is absorbed and kept in much higher concentrations in blood, crosses your blood-brain barrier and is a neurotoxin. I avoid msg in foods or try to. Read about this. wiki is enough I think. Atleast make yourself clear about the difference between the glutamates and their absorption in the gastrointestinal tract. being protein bound and free and all... Rmraihan (talk) 22:13, 31 October 2012 (UTC)

And If you have read that discussion before. You should know that I am more than happy to provide you enough published sources. and authority that is bound to be enough for our progeny discussing this article. But if you ARE intentionally refusing to accept the Scientifical or logical view about stimulants and psychoactive drugs and say intentionally uninformed things I refuse to do so. I know you might not have read all I've said before so I'd like to tell you something that doesn't require you to be a muslim but needs some of your will. Go out. Grab a Muslim(who reads quran/hadith a little and isnt entirely atheist-like). and Ask. are Psychoactive Drugs/ ALL DRUGS "PROHIBITED" or not in ISLAM. Please do this. Dont think this is a vague thing for us. this is a clear thing. but the problem is not with the muslims. its a problem that was with even me, a few years back. few caffeine users accept that caffeine is a psychoactive drug. We just take it in a small amount. But doesnt mean its not. Lets just leave it to science and do what you are required to. dont reinvent stuff. If you're unclear about what I said about "future" back then, Im afraid I cannot bring that up again. We are clear about psychoactive drugs. But caffeine is a new thing for Islam. what reason accepts is not accepted by most muslims. We are not here to discuss public opinion. We just discuss reason. Yes its a psychoactive drug. Yes all Muslims know Psychoactive drugs are prohibited. Yes Their understanding of psychoactive drugs and the definition of Science is nearly synonymous. If you have a problem with any of the Yes s tell me which one. If havent still gotten out. Ill know. Because you'll have problems understanding me. If you dont understand what people actually think. THOUGH THEY DRINK COFFEE THEY DONT ACKNOWEDGE IT AS A PSYCHOACTIVE DRUG. NEARLY ALL OF US DONT. NOT ONLY MUSLIMS. Rmraihan (talk) 22:28, 31 October 2012 (UTC)

First, MaxEnt, not READING what I wrote before you break most of the rules wikipedia might contain. As for "The main point I would emphasize is that you can't make demands of other Wikipedia editors based on their knowledge or lack of knowledge of Sharia law..." thing you said without reading any of what I said before. Please know that your claim is, false, if I consider you have read what I wrote. And Intentional too. I never demanded shariah knowledge. I said If you dont know about shariah that page ought to become a very long argument. I was never inadequate of logical or analytical advancements. I never stopped Advancing logically demanding HIS knowledge. I only said again and again that : HE WILL ASK QUESTIONS HE OUGHT NOT TO, ABOUT WHICH THERE IS NO CONFUSION, SO I HAVE TO EXPLAIN THEM ONE BY ONE. AND THAT ARGUMENT WILL BE MULTIPLE TIMES THE ORIGINAL POST LENGTH. Do you follow what I was and am trying to say? for instance he demanded a fatwa from me. that was outrageous. I had explained him what fatwa was using original wikipedia text explaining to non-muslims the popular misconceptions. now if he has problems to digest that, what do I do? give him laxatives or something? can you suggest me some? If he had advanced logically, there would be no demands of shariah laws. But he refuses to do so, he doesnt know anything or has misconceptions and wouldnt accept anything further. I only demanded shariah knowledge because of a complain. the complain that I have to write so many things. that a muslim wouldnt be asking me. not only that, I have to source everything I say. simplify it many times for him. and give him wiki text(like fatwa's..) but he refuses to accept even that! this is a lot of burden! why should I progress any further? I am only complaining, but I never refused to progress. Your increasing my burden by not keeping a muslim friend beside u when you're talking.! Rmraihan (talk) 23:07, 31 October 2012 (UTC)

There might be some gaps pertaining to me answering your posts on this talk page. sorry, but I cannot be someone's work ass. If you disagree with what is on the wiki on the religion section. Next time YOU BRING YOUR SOURCES AND PROVE YOUR WAY THROUGH THAT IM THE ONE WHOS WRONG. ADVANCE LOGICALLY. OR REGRESS LOGICALLY WITH SOURCES. because Im tired of answering to non-muslims asking me of common muslim stuff. And computer science students thinking they are bio-geeks. Rmraihan (talk) 23:12, 31 October 2012 (UTC)

I also have problems with "from what I find". what you find is Google. what you only take for bible is google. but google doesnt list hadith. we muslims dont google about drugs. we find hadith. then we are without unsurities. Dont you understand that I myself, too, know there is little implication on Google what shariah considers Drugs? You get many things in Google BUT THE CHIEF THINGY you ought to have found is what MUSLIM PEOPLE CONSIDER PSYCHOACTIVE DRUGS. THOUGH UNNECESSARY FOR OUR ARGUMENT AS IT HAS PROCEEDED BEFORE. IF YOU KNEW, YOUR CONFIDENCE YOU CERTAINLY INCREASE A LOT! WHAT WE COMMON PEOPLE CONSIDER DRUGS! WHAT THE WORD "INTOXICANT" MEANS TO US. STUFF LIKE THIS. I give you published references to you in this matter. but to no effect. because you're unsure about people's opinion. Its not the GOOGLE THEN THE PEOPLE is who you should consider as your source of information! Rmraihan (talk) 23:26, 31 October 2012 (UTC)

In few words, what you need to really know aside from anything else is- What I am talking about is a clash between people's regarding caffeine as a psychoactive drug(scientifically). And Science. The clash is NOT between ISLAM and people's understanding of ISLAM's definition. no. that is a problem with you people. And be advised that by ISLAM, we mean other things than you mean by CHRISTIANITY. Who has the right to change and romanize even their prophet's name! invent rituals and stuff. Theres no authority in Islam like that. Im again giving you the excerpt pertaining this matter which looie refused to digest: from fatwa (wikipedia- section - misconceptions about Fatwa) "A fatwā is not automatically part of Islamic teachings. While the person issuing it may intend to represent the teachings of Islam accurately, this does not mean that that person's interpretation will gain universal acceptance. There are many divergent schools within the religion, and even people within the same current of thought will sometimes rule differently on a difficult issue. This means that there are numerous contradictory fatwā, prescribing or proscribing a certain behavior. This puts the burden of choice on the individual Muslim, who, in case of conflict, will be forced to decide whose opinion is more likely to be correct." And please read the first lines of this paragraph carefully. there is no clash between islam and people. the clash is between science and people. People ALREADY took what islam says, varbatim. People YET DIDNT TAKE what SCIENCE says. this is a problem. and if you fail to see why this problem erupted you deserve no more replies whatsoever. this is a problem with FUTURE. STUFF WILL COME IN FUTURE WHICH PEOPLE MIGHT BE UNINFORMED IN. WE ARE NOT CONNECTED TO UNIVERSAL KNOWLEDGE GRID. WE ARE NOT "UPDATED" BEINGS. Science might go further. But people didnt. (talk) 00:10, 1 November 2012 (UTC)
Ah caffeine, "the wine of Islam". My favourite type? Arabic, definitely. In all seriousness, coffee has been controversial in Islam - despite the love affair with the substance in many Muslim countries - and there appear to have been two interpretations - one allowing for its use as not specifically proscribed by the Quran and another endorsing a wider interpretation of possibly transgressive behaviour. The text should represent both interpretations of Sharia Law but also reflect the rather massive scale with which many populations in predominantly Muslim countries both historically and in the present have consumed coffee. This seems a reasonable English-language source to me.FiachraByrne (talk) 02:47, 1 November 2012 (UTC)
I guess the point to make would be that occasional attempts by religious conservatives to ban coffee on religious grounds have been spectacularly unsuccessful in Islamic countries. This is hardly surprising given the historical importance of Middle Eastern and North African cultures to the history of coffee. Indeed the word coffee itself is Arabic in origin (qahwa ... with the "w" pronounced as "v") and, of course, the sacred bean is grown on the Coffea arabica. Further, the coffee trade was effectively controlled by Middle Eastern traders until the end of the 18th century. [4] FiachraByrne (talk) 03:23, 1 November 2012 (UTC)
Quite a good source on the "coffee debate" in Islam. [5] FiachraByrne (talk) 03:23, 1 November 2012 (UTC)
Source-book on Islamic criminal law relating intoxicants, including coffee: [6] FiachraByrne (talk) 03:23, 1 November 2012 (UTC)
More on the 16th century coffee debate [7] FiachraByrne (talk) 03:23, 1 November 2012 (UTC)
Now there's something else I didn't know - "Mocha" is the name of chief port in Yemem and which had a major role in the coffee trade (as Yemen had a monopoly of coffee production). [8]
@Rmraihan. What are your sources? At Talk:Rmraihan/Islam and Caffeine all I can see are a couple of quotes from the Quran and other primary sources. I can verify that there's been a modern movement to have coffee considered an intoxicant but I have no sense that this is anything other than a fringe or at least non-mainstream interpretation. Do you have any secondary sources that support the interpretation of coffee as an intoxicant under Islamic Law? Do you have any secondary sources that support that this interpretation is mainstream? FiachraByrne (talk) 04:20, 1 November 2012 (UTC)
Though I salute you honestly for actually reading about this and not quoting some Salah al-din unknown crap without any reference to what arguments or logics he himself used to get to a conclusion. Yet the mistake you are doing is same as what your predecessors did. You are "unsure" about the popular opinion. And TOO SURE that they DONT SHUN ALL PSYCHOACTIVE DRUGS BY RULES OF ISLAM. Now I want to give you some info, and I would like to know your thoughts about it. Because it is a so simple fact that spoils water on ALL THE REFERENCES AND HARD WORK YOU DID. DO YOU KNOW smoking tobacco is actually shunned by islam, people know this, and yet they are completely legal in Saudi Arabia? You are definitely making a mistake crossing the point that marks religion and politics. Politics are always different. It WAS NEVER ISLAMIC TO KILL MUHAMMAD's(PBUH) GRANDCHILDREN. NOR WAS IT TO SELL SAUDI ARABIA TO AMERICANS AND banish islamic democracy and establish the "throne" of american... this goes a long way. And as I have already discussed if you have problems pertaining to what science says about caffeine then you should refrain from discussing any more whatsoever. this is not a humanities article. Does the fact not go into your little brain that "CAFFEINE" being a psychoactive drug is a quite modern knowledge. it hasnt even spread to most of its users. no not in the 17th 18th or 19th century, even most of 20th century people only could "DOUBT" they could never prove that it was one. Please. Dont confuse science with humanity and history. Science is knowledge beyond doubt. What our elders doubted is their burden not ours. Lastly, I want to again tell you. Please go OUT. Grab a good muslim. and ask him! not google! your logics are really messed up because you believe muslims are confused about psychoactive drugs while they're not! they are only confused about caffeine and any new drugs like this would come and science tells us clearly what they are! (talk) 08:32, 1 November 2012 (UTC)

And another thing, just do the go-out crap I mentioned. Its really important for our argument. And the three things I told you to ask christians and muslims in my verbose exchange. Books remain very elusive about common knowledge. Theres just no need for them to write! You still would have some doubts. Which I will answer, but not before I fix things up with you. And if my subject keeps changing, How can I educate all of them? And this movement crap you again mentioned despite all the clearing I did on looie. Really deserves a no answer. You first read my argument and ask specefically on what you have problems. I cannot answer oblivious-to-me questions again and again to any new person who sprouts up. Rmraihan (talk) 08:40, 1 November 2012 (UTC)

And again you talk about things without reading about them. How dare you again say my sources are primary? Did you or did you not READ the HEATED CONVERSATION between me and looie? Dont you understand? You are unsure about my saying that PEOPLE'S DEFINITION OF PSYCHOACTIVE DRUGS AND THEIR TRUE DEFINITION. ARE SAME! You are only unsure about it. Whatever I give you has no effect on you. Because all you trust is google. If you doubt one line by me, then doubt only that! dont just vomit everything I say! If you dont want to advance logically then dont continue. You are very irritating because you havent read what I said about sources to looie. If you read that and if a question arises in you pertaining that Im more than happy to provide you sources and make you clear about what you want to know. And I assure you I can do that. But what I cannot do is your repeated agnosticism to READING, SCIENCE, and HISTORY POLITICS! Please. Go out. grab a muslim. and make yourself confident about advancing yourself in my argument. The only reason you are repeatedly making clear waters blurry is because you're still unsure! Get some confidence if u wanna talk. I cannot waste myself teaching you history science and politics. Common muslim knowledge and stuff. this is outrageous. You WOULDNT READ WHAT I SAID. ARGUE WITH ABSURDLY INADEQUATE KNOWLEDGE OF SCIENCE IN A SCIENCE ARTICLE. KEEP CHANGING PEOPLE WHEN I CLEAR THINGS UP. SO NEW BURDENS SPROUT THAT NEED READING, AGAIN! Rmraihan (talk) 08:52, 1 November 2012 (UTC)

Coffee was not mentioned in primary sources specifically. As they didnt exist before 13th century and was in business like this after 19th century. It has always BEEN the source of a DOUBT, that its a psychoactive drug. Until recently, when its classified as a psychoactive drug and its benefits are contrasted to its psychological effects. So many secondary sources existed in the 16th to 19th century which carry INCOMPLETE arguments. until recently. when the primary sources, its common interpretation,(not secondary source or movement! common muslim interpretation!) and science fit into the logic puzzle that declares it prohibited. secondary sources are never a problem in this respect as I have discussed way back, and they are abundant. the puzzle piece missing from the people is not the primary source, nor the interpretation of it. the puzzle piece missing is the one of Science. teach a muslim science and he'll too declare Caffeine specifically prohibited. People might not know science. But does that mean it doesn't exist? Or that because THEY dont know science we CANNOT ADVANCE LOGICALLY HERE.!Rmraihan (talk) 09:13, 1 November 2012 (UTC)

Fiachra, sorry for being lengthy. But I have said nothing here that I havent mentioned before. And its your fault for not following up. You have no one to blame but you. I could not leave the page as it was before could I? Then your UNREADING attitude would settle this dispute as settled. In your favor! Rmraihan (talk) 09:16, 1 November 2012 (UTC)

@Rmraihan - even with my little brain, the logic of your argument is clear. Islamic law prohibits intoxicants. That caffeine is a psychoactive substance, and therefore an intoxicant, has only recently been established scientifically. Historical interpretations of the status of caffeine could not have known this and are therefore deficient. Given our present state of knowledge caffeine must be considered a forbidden substance for any Muslim (although whether or not they individually adhere to this is another matter and largely besides the point). You have convinced me of this, sincerely. However, all of this is, unfortunately, irrelevant to Wikipedia. This is so as I've yet to see you actually cite a reliable (i.e. scholarly) secondary source that promotes this argument. That means that such a source would not only have to say that intoxicants are forbidden under Islamic Law but that caffeine should also be considered an intoxicant. In the argument above you appear to be making this connection yourself. That is insufficient for Wikipedia, even if it is true and logical (see WP:Truth), as it necessarily depends on your own synthesis (WP:SYNTH and WP:OR). Both the Quran and hadith are primary sources of course and should, for WP, never be interpreted by an editor. You must rely on a secondary source to do this interpretation for you. Actually, I've linked to a tertiary source above which points to a secondary source that indicates that some modern interpretations of Islamic Law consider caffeine as an intoxicant and therefore forbidden. However, you'd still have to establish that this was not merely a fringe view but of sufficient weight to merit inclusion in this article. Also, the scientific status of caffeine as a psychostimulant is irrelevant if this point has not been raised by qualified Islamic scholars. You cannot make these connections yourself. FiachraByrne (talk) 14:19, 1 November 2012 (UTC)
Just to be clear, the establishment of whether this is a fringe view does not depend upon upon a determination of popular opinion but, for this topic, the weight of opinion amongst qualified scholars of Islamic law. FiachraByrne (talk) 14:25, 1 November 2012 (UTC)


The bottom line is: No reliable secondary source = no edit to article. The hadiths themselves are clearly primary sources and cannot be used for this purpose.

Suggested edit: Remove entire unsourced paragraph that currently reads "Although every psychoactive drug is prohibited ... widely consumed psychoactive substance." and replace it with:

  • "Some Muslim authorities have considered caffeinated coffee to be a forbidden 'intoxicating beverage' under Islamic dietary laws."[7]

using this Encyclopedia of Islam as our reliable secondary source. The author of the encyclopedia has a Ph.D. in the History of Religions, and is an Associate Professor of Religious Studies in History of Religions (Islam) and Arabic at UCSB. Good? Zad68 15:46, 1 November 2012 (UTC)

Here is another book by a Ph.D. in Islamic studies and it confirms the same thing, and even mentions caffeine directly. Zad68 15:56, 1 November 2012 (UTC)

That looks reasonable, Zad68. Axl ¤ [Talk] 18:55, 1 November 2012 (UTC)

Thank you! Thank you, to be gallant as for the reason's plight! I have immediately reverted the original article to a position advanced by our mutual argument. Yet I have left a bit of that "clearing" to do (Just enough already!). I shall not take any common system of information dissemination granted from here on out, so as to avoid confusion in the future generations reading this as the context here might not be same as the model used in Science, or History. I will also try to quote reasons directly from Wikipedia Sources related articles, as they are the main basis of what I shall present here. Though I will state nothing new, it has been "oversimplifiedtrollversion"ed before, as my peer ressisted progressing in his reason. The mistake looie did, was to assume that the writer must have no argument of his own in the concussion altogether. Though that is not supported by reason as I've already mentioned there. He failed to see the wikipedia policy on this and just based his assumptions on the talk between many wikipedians. There MUST be an argument of MY OWN as the reason implies. BUT The wikipedia policy does not collide with this! Only looie's thought did! What he didnt know was the writer does in fact present an original analysis! THE BURDEN of whatever I write IS SOLELY ON ME. BUT as to the problem of verifiability, MY ARGUMENT cannot ADVANCE to a position already advanced by verifiable(published) sources.(According to common models of Science and History, Secondary and Tertiary Sources) (What looie assumed had a problem, multiple tertiary sources colliding with each other. And If I can not think of my own then which one of them shall win the war. This assumption is altogether unreasonable, non-existant, and based on talk between wikipedians only. Just talking about sources doesnt mean ur pro on Information Dissemination.) The ARGUMENT shall be itself BASED on Reliable Sources.(According to common models, Secondary, so as to verify the reliability of the primary source. Like an historical first hand account is primary. And its reliability is Secondary) And BASING THEM it can only ADVANCE to a position of analysis as presented before in another published(preferrably) analysis(common models:tertiary) to be attribitued as source! And though the debate I shall now present is entirely unneeded for the construction of the argument that will advance, I need to do for the future people reading this. this will be between hyphenations. -Though DO NOT assume that the Primary sources are solely primary sources in this context. As historical first hand accounts and Scientific Original Research needs to be verified. Islamic sources do not. They are itself Both primary and secondary sources. This means any analysis of them might have higher levels of information dissemination. But the source is already present. It is as reliable as the secondary sources citing it!- Now if I move up another level in information dissemination to the existance of published sources analysis that has advanced as much as I have presented in my argument. They are already present and I was always ready to give them after I settled the confusion in looie's little brain. (secondary sources=reliable info= base of argument, tertiary source=some else's analysis= proof of non originality of my advancement) Now, as I have cleared about my sources. The three lines I have presented I can already source accordingly.(though it is a pain now for me as google books cannot be accessed without a proxy from here, zad's source would definitely add to the list) Rmraihan (talk) 02:21, 2 November 2012 (UTC)

Though what I write will have their verifiability problem fixed in the future, as our argument would come to mutual conclusion. There is another problem about my argument that needs clearifying according to wikipedia policies. You didn't point it out. I will present the argument about that once it arises. And I hope to be successful about that too, not increasing the load on you right here, right now! Rmraihan (talk) 02:29, 2 November 2012 (UTC)
These walls of text don't do you any favours. IRWolfie- (talk) 10:31, 2 November 2012 (UTC)

The wording in this source [9] appears to indicate that coffee isn't typically prohibited. We appear to be reporting the views of some small number of individuals (as the wording indicates), but not saying what the standard Islamic perspective is. IRWolfie- (talk) 13:54, 2 November 2012 (UTC) Zad, I'm sure this [10] is what the majority of sources probably say; the issue is that the current references don't seem to say it from what I can see. IRWolfie- (talk) 14:31, 2 November 2012 (UTC)

Sure, "widely consumed by Muslims" is a paraphrase of Campo pp. 154-155, read the paragraph "The coffee prepared..." and the sentence "None of these efforts to prohibit..." Also see Brown, the few pages starting at p. 149. I think it's a reasonable paraphrase.

I agree that post-16th century debate over caffeine isn't really significant. New proposed content:

Caffeinated beverages are widely consumed by Muslims today; in the 16th century, some Muslim authorities made unsuccessful attempts to ban them as forbidden "intoxicating beverages" under Islamic dietary laws.[7][8]
dropping not very significant-looking Warren and using Brown instead. Zad68 15:01, 2 November 2012 (UTC)
  1. ^ Hofmann WW. Caffeine effects on transmitter depletion and mobilization at motor nerve terminals. Am J Physiol. 1969 Mar;216(3):621–629.
  2. ^ Merck Index
  3. ^ Merck Index
  4. ^ Aquaculture Nutrition Volume 14 Issue 5, Pages 405 - 415 "Effects of dietary caffeine on growth, body composition, somatic indexes, and cerebral distribution of acetyl-cholinesterase and nitric oxide synthase in gilthead sea bream" and Naunyn-Schmiedeberg's Archives of Pharmacology Volume 356, Number 5 / October, 1997 "Caffeine induces central cholinergic analgesia"
  5. ^ The Journals of Gerontology Series A: Biological Sciences and Medical Sciences 63:149-150 (2008)
  6. ^ Caesar, R.; Warringer, J.; Blomberg, A. (2006). "Physiological Importance and Identification of Novel Targets for the N-Terminal Acetyltransferase NatB". Eukaryotic Cell. 5 (2): 368–78. PMC 1405896Freely accessible. PMID 16467477. doi:10.1128/EC.5.2.368-378.2006. 
  7. ^ a b Juan Eduardo Campo (1 January 2009). Encyclopedia of Islam. Infobase Publishing. pp. 154–. ISBN 978-1-4381-2696-8. Retrieved 1 November 2012. 
  8. ^ Daniel W. Brown (24 August 2011). A New Introduction to Islam. John Wiley & Sons. pp. 149–. ISBN 978-1-4443-5772-1. Retrieved 2 November 2012. 
That's ok by me. IRWolfie- (talk) 15:05, 2 November 2012 (UTC)
 Done Applied. Zad68 15:16, 2 November 2012 (UTC)
@IRWolfie- Sometimes using brawn instead of brain spoils things instead giving you awards for hard-work! Specifically mentioning and bringing forth 16th Century! Even though I thought I made myself clear why it would be non-sensical! Even if you do disagree with me on that particular point and you have a far more logical view to share and Im very nincompoopy comparing you, that point isn't undisputed. And fringe theories?? Are you mocking yourself or me? Sharing your christian attitude and what "seems" to you the mainstream idea, might not be! Atleast if you only didn't mention 16th century particularly Wolfie, Then I would have save for you some respect as a wikipedian. sure it doesn't help you too doesn't it? Only do the unreading unmeaning tubelights refer text as WALLS (predicament isn't it? READING THROUGH! ??) however unworthy might be, as walls. Rmraihan (talk) 09:41, 3 November 2012 (UTC)
I'm not a christian, and I was speaking of mainstream islamic thought. IRWolfie- (talk) 10:07, 3 November 2012 (UTC)
You are! It is not about what you do, it doesn't matter whether you go the church or not. You were raised by christian parents. As for the article, Ill soon too excercise brawn over you once I contact one of my old friends. Until then, dont consider me to be logical or something. I made my points. If you had disagreement you could say, but that unnecessary fact that you brang up concerning 16th century surely proves you never read it. what is reasonable and what is not if you dont even know what they are? By citing the 16th century you are making things seem like what they are not in reality. If you dont have any reason to follow up everything here, like fiacra and write something reasonable, then why bother posting here? What logic can I say to you without making it long, when it's already posted! Rmraihan (talk) 13:34, 3 November 2012 (UTC)

And the false delusions of "mainstream islamic thought" you live in either emerged from those Children's encyclopedias about muslims summing them up for christians or some detached muslim like you who can only give him his incomplete opinion. No not like you, atleast you read a little about your religion. I seriously doubt that you even contacted any muslim-name atheist in your country, far less you would ever even talk to a mainstream muslim in a muslim country in all your life! Why do you even come here? did you ever read one hadith in your life, just out of mere curiosity?? Rmraihan (talk) 13:43, 3 November 2012 (UTC)

On second thought, wolfie boy. I can give you some presents next christmas as your punishment some books! and know what books Ill give to you? Books by MUSLIM WRITERS (VERY POPULAR IN MUSLIM COUNTRIES) about the laws of Christianity. Once you read them. You'll understand how mocking are the sources you provide are to muslims. Though It'll be much more fun if you cant finish and keep them books your home. Hope you get scared and say OMG every time you walk past them! Rmraihan (talk) 09:51, 3 November 2012 (UTC)

Even though reading is obviously a true chore for you, Ill sum you up only the points it was made clear before by me. Only the parts which were not doubted, or otherwise disputed.

1. Islamic Primary Sources, My own logical interpretation, Their common-street-muslim public Interpretation AND many tertiary or secondary sources are clear that by the common definition supplied by science, all psychoactive drugs are prohibited.

2. This thing is not easily found in Google. long story.

3. Google is not "search muslim countries for their common belief". If you deludedly think that, You'll get a christian diseased view that is unsupported by us.

4. Unto this point everything is clear. what follows is not.

5. There is no movement against caffeine specifically. Nor is against tobacco which is specifically believed by common muslims as prohibited. (I WONT SOURCE THIS, GO ASK SOMEONE FROM A MUSLIM COUNTRY)


7. Most caffeine users think caffeine is NOT a psychoactive drug. so do muslims. The concepts of science didn't reach them.

8. It is also very serious to cite 16th century movements. There were movements like this in your own religion too. SCIENTIFIC FACTS DID NOT EXIST THEN. so our interpretations of primary sources and worldly facts did not coincide. now they do.


10. Digest this. ill talk later. — Preceding unsigned comment added by Rmraihan (talkcontribs) 14:11, 3 November 2012 (UTC)

First, please, ALL calm down a bit. Anger is the clear path into destruction and trouble overall. Rational discussion cannot occur in that way! Discussion CAN, if one remains calm, yield results that are acceptable to all. Now, that said, let's review some nations I know directly drink loads of caffeine beverages (colas, tea, coffee). Saudi Arabia, Iran, Kuwait, Iraq, Turkey, Indonesia, Pakistan. Just for starters. Only ONE nation had a policy that considered coffee haram, Arabia, when one governor saw a captain of the guard serving the new beverage to his men, passing along the bowl like wine used to be served. Hence, he punished the captain and declared it haram. That changed over time, due to it not being an intoxicant, which IS what is haram. You innovate in the faith when you stretch anything psychoactive as haram, for medications and even foods are known to be psychoactive, but halal. If you wish to claim that caffeine is haram, you first have to explain what school claims that is so, then provide citations that are relevant to the world at large. Not a group that essentially 99% of the Islamic world has never heard of, as that isn't noteworthy and is suspiciously like innovation in faith.Wzrd1 (talk) 06:07, 12 November 2012 (UTC)

Caffeine half-life

The half-life documented here is 4.9 hours. Many sources on the web are using 2.5 to 4.5 hours. The two citations used here for the half-life are poor. One is presently a broken link, and the other is mainly a discussion of metabolism anomaly (IIRC from my quick glance). Google Scholar found a couple of papers that appeared to resolve this, but the necessary bits are behind a paywall. It would be good to cite one of the actual studies used to characterize half-life in people with normal metabolism. Note: there are studies out there with extremely poor population sizes. One had a population of normal individuals with just three members. — MaxEnt 18:41, 30 October 2012 (UTC)

The half-life seems to be quite variable, even among people with normal metabolism. If you would like to change the value and have a good source, I have no problem with that. Looie496 (talk) 23:41, 30 October 2012 (UTC)

Edit request on 2 November 2012

Please change: "Caffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug and an acetylcholinesterase inhibitor." to: "Caffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug."

There really is no evidence to support the claim that caffeine or any xanthine is an acetylcholinesterase inhibitor. The citation for this claim is week at best. There is little structurally that would suggest caffeine to be one and this in a very well understood area (acetylcholinesterase inhibitors). I would suggest finding more to support this claim or remove the statement. Or at a minimum remove it from the FIRST line suggestion that this is a clear mechanism of action of caffeine. (talk) 21:14, 2 November 2012 (UTC)

Done as requested. If somebody provides a better source we can revisit the issue. Looie496 (talk) 23:49, 2 November 2012 (UTC)

Response to issue - That was my fault. Sorry about that :) — Preceding unsigned comment added by 00AgentBond93 (talkcontribs) 18:22, 15 January 2013 (UTC)

Edit request: pharmacology section

Under mechanism of action:

" Consumption of caffeine antagonizes adenosine and increases activity in neurotransmission including acetylcholine, epinephrine, dopamine, serotonin, norepinephrine and glutamate."

Caffeine can be an antagonist of an adenosine receptor, not of adenosine (a structurally similar small molecule).

Would also re-word second half of sentence. List is of molecules that can act as neurotransmitters. Citation would be nice. — Preceding unsigned comment added by (talk) 04:47, 11 December 2012 (UTC)

This sort of usage may be strictly incorrect but it is very common. It seems to me that people who know what an antagonist is will probably understand what is meant here, but I welcome other opinions. Looie496 (talk) 19:48, 11 December 2012 (UTC)
I'll second the suggested changes to the mechanism of action. Also, the list seems incomplete. There's no mention of caffeine's antagonism of inhibitory GABA receptors or of caffeine's upregulation of gluconeogenesis. I realize that antagonism of adenosine receptors is considered the primary mechanism of action by most doctors (though an up-to-date source showing it's still considered primary would be helpful), but it seems like the peer reviewed literature points to a more diverse range of effects.
After the neurons were treated with caffeine (0.1~100 micromol/L) prior to the application of GABA (100 micromol/L) for 30 s, GABA-activated inward currents were obviously inhibited. Caffeine shifted the GABA dose-response curve downward and decreased the maximum response to 57% without changing K(d) value. These results indicate that the inhibitory effect is non-competitive. The pretreatment with caffeine (10 micromol/L) inhibited I(GABA) which was potentiated by diazepam (1 micromol/L).
Effects of caffeine on gluconeogenesis and urea synthesis induced by alpha-adrenergic stimulation in suspensions of rat hepatocytes.

...Therefore, we suggest that stimulation of gluconeogenesis and urea synthesis by phenylephrine is due to increase in [Ca2+].
Further, Caffeine is broken down by MAOs, and anything which occupies these enzymes has the potential to upregulate monoamine levels in the brain. There's a lot of recent research in this general area (.

--Ryan W (talk) 08:53, 2 January 2013 (UTC)

Since you obviously know quite a bit about this, if you feel that these effects are biologically relevant, then I hope you will feel free to improve the article -- bearing in mind that the article is read by millions of people each year and ought to be kept as broadly accessible as possible. Looie496 (talk) 15:22, 2 January 2013 (UTC)

Response to editing - Hello. I have read your section and I have recently read the article "Health effects on Caffeine". The section where is states it inhibits GABA (in higher doses) and increases cortisol levels is explained here. There are citations explaining the drug's pharmacological properties. If there are any more issues, you can contact me on my user talk page. My user name is 00AgentBond93. Thank you very much.

Psychological effects (Subtle but important grammar edit)

A few suggestions for an edit

"At high doses, typically greater than 300 mg, caffeine can both cause and worsen anxiety[51] and rarely trigger mania and psychosis."

Here, the lack of comma seems to suggest that the last clause intends to dispute the prevalence of caffeine-induced mania. Just guessing, but I think the author intended this to read as the following:

"At high doses, typically greater than 300 mg, caffeine can both cause and worsen anxiety[51] and, rarely, trigger mania and psychosis."

Here, the commas surrounding "rarely" gives the final clause a more neutral tone.

If our goal IS to dispute the prevalence of caffeine-induced mania, a better flow (in my opinion) would be:

"At high doses, typically greater than 300 mg, caffeine can both cause and worsen anxiety[51]. Caffeine may also trigger mania and psychosis at these doses, though this is ...rare/disputed/blahblah...[insert source]."

Normally I would just make a grammar edit, but here making that edit would change the meaning. — Preceding unsigned comment added by (talkcontribs)

I changed the sentence to read "or, rarely, trigger mania or psychosis". Will that do? Looie496 (talk) 04:25, 8 January 2013 (UTC)

Condensing and/or removing some information on the "Caffeine" article

In my opinion, this drug article may be too long for readers. If someone gets the chance, please shorten the page. However, I have just fixed the "Chemical box" two days ago; and there shouldn't be any condensing on the Chemical box part. — Preceding unsigned comment added by 00AgentBond93 (talkcontribs) 18:04, 15 January 2013 (UTC)

Caffeine - Pseudoalkaloid, specifically a purine

Caffeine is a purine pseudoalkaloid, as it is not derived from amino acids like true alkaloids. Shouldn't there be something in the article to reflect this?

Adverse effect to caffeine.

I would appreciate a bit more on caffeine's effects on ADD/ADHD. I can say I know it works on calming & focus, but it's not the same as backing it up with citations. — Preceding unsigned comment added by (talk) 00:26, 28 February 2013 (UTC)

New image

I've added a space-filling molecule of the chemical substance (if it's no trouble) — Preceding unsigned comment added by 00AgentBond93 (talkcontribs) 18:21, 6 March 2013 (UTC)

Edit request on 16 March 2013

remove the spammy links on citation 76 (talk) 05:34, 16 March 2013 (UTC)

You're quite right -- I've removed them. Looie496 (talk) 06:14, 16 March 2013 (UTC)

Autonomic effects of caffeine?

"With heavy use, tolerance develops rapidly to the *autonomic*, but not cognitive or arousal effects of caffeine."

What exactly ARE the autonomic effects of caffeine. This is not explained in the article.  :( — Preceding unsigned comment added by (talk) 02:52, 22 April 2013 (UTC)

I've added a couple of examples of autonomic effects (increased heart rate and muscle twitching). I hope that will suffice. There is more information in the body of the article. Looie496 (talk) 03:28, 22 April 2013 (UTC)
Also, is their any citations on the original quote? I haven't read anything before about a selective tolerance to certain effects but not to others in caffeine. HouseJoffrey (talk) 17:08, 24 May 2013 (UTC)
I was just doing some research, and I think that this statement is false. According to a study (PMID 8246157) there is an up-regulation of adenosine, the neurotransmitter that makes you drowsy that caffeine inhibits, with the consumption of caffeine. This would mean a tolerance is developed for the arousal effects of caffeine (and possibly also the cognitive effects). HouseJoffrey (talk) 13:43, 28 May 2013 (UTC)
That's interesting, but it's a 20 year old paper with a rousing total of 11 citations (according to Google Scholar); and the word "apparent" in the title is not exactly compelling. For this to be worth discussing in the article, I think we would need to have a stronger source. Looie496 (talk) 14:00, 28 May 2013 (UTC)

Problem in the history section

The article presently claims "...two bills were introduced to the U.S. House of Representatives in 1912 to amend the Pure Food and Drug Act, adding caffeine to the list of "habit-forming" and "deleterious" substances..." with a citation that points to an article that is poorly written, completely unsourced, obviously consists largely of unsupported opinions and - most of all - does not mention, anywhere, any such legislative action.

I'm willing to suppose that the actions in Congress may have happened, but there is no support whatsoever for that idea in the webpage cited. I would like to request that the claim be either properly suppported or removed. I tried to find support for it, but could not do so; however, I don't claim to be good at researching legislative history. Poihths (talk) 01:36, 5 May 2013 (UTC)

This volume of Congressional hearings makes it clear that two such bills were indeed introduced, see pp 597 ff (parts of which are pretty amusing). It's not an ideal source because it doesn't actually give the text of those bills, only testimony regarding them. If anybody can dig up a document that actually gives the text of the amendments, that would be better. Looie496 (talk) 03:06, 5 May 2013 (UTC)


Coold some one add something about decaffeinated tea as, in the UK at least, it is becoming very common? (talk) 21:37, 22 May 2013 (UTC)

Request for edit: Inclusion of Pre Workout Products in Caffeine Contents Table

Several products sold as 'pre workout' powders have various stimulants in them. Most of these include a large amount of caffeine.

I only know of 3 products caffeine levels but I propose to research into other products as well.

For reference the products I know of are

  • Craze by Driven Sports (DS Craze) 80mg Scoop. Serving Size 2 Scoops\Day. 160mg.
  • 12 Gauge Shotgun by VPX (VPX 12G Shotgun) 250mg Scoop. Serving Size 1 Scoop\day. 250mg
  • Mesomorph 2.0 (Not sure of manufacturer) 300mg Scoop. Serving Size 1 Scoop\day. 300mg.

Of course there are many others out there and if the table feels too bloated with this inclusion I suggest something like "Preworkout Powders: 80mg-300mg/Serve" be added to the table.

I'm not sure about wiki's page on PWO's in general but might set about creating or expanding one if I can get around to it.

I will make the edits myself in 4 days time (just registered) if no one else objects or does it for me. Please feel free to discuss this proposal. I'm new to Wikipedia editing and want to get off on the right foot - without breaking any rules etc.

I do use these PWO's but am not affiliated with any of the companies that make them etc. I wish I was, they are not cheap! ;)

Cheers - Kagalive1985 Kagalive1985 (talk) 13:56, 26 July 2013 (UTC)

Legality Section needs info on current limits

The article says "Today, caffeine is legal and available in many forms in all jurisdictions.[citation needed]" This is not completely true, it is legal is certain sized doses and within certain limits. I think we should have some info on those limits, in particular when it comes to prescription levels of caffeine. I did some searching and found the US limit of caffeine in soft drinks is .02%ADNewsom (talk) 18:44, 30 July 2013 (UTC) (Primary: (Secondary: Anybody have the time to integrate this into that section? I would but alas, protected. Then we could remove that [citation needed] since my source also says that caffeine is otherwise legal (in the US) ADNewsom (talk) 18:44, 30 July 2013 (UTC)

Yeah lol my other tab wasn't logged-in... semi-protected. Still could use more work, but I added some. ADNewsom (talk) 19:15, 30 July 2013 (UTC)

Edit request on 2 August 2013

caffeine can increase testosterone level when doing physical exercise (talk) 20:50, 2 August 2013 (UTC)

Per WP:MEDRS, we don't ordinarily make use of individual primary research studies -- especially when, as in this case, the article is in a very obscure journal and has never been cited by any other paper. Looie496 (talk) 21:56, 3 August 2013 (UTC)

Edit request on 2 September 2013

Please change the 2D diagram of caffeine that is in the top right corner when the page is first opened. The structure in that image shows the nitrogen atoms bonded to hydrogen, while actually each nitrogen is bonded to a methyl group (CH_3). This is depicted in the 3D space filling model already. (talk) 00:12, 2 September 2013 (UTC)

The diagram is correct. In a standard skeletal structure, a dead-end line is a methyl group (just like any unlabeled position is a carbon, for example, the non-"N" corners of the rings) rather than a hydrogen atom. DMacks (talk) 01:32, 2 September 2013 (UTC)

Edit request Oct 4th 2013 - decaff section

"Decaffeinated" coffees do in fact contain caffeine, although only about 10 mg per cup as opposed to 85 mg per cup for regular coffee."

This statement needs to be edited. The linked source states that at least one sample of decaff coffee contained no detectable caffeine, so the statement as written is overly broad in scope. The study was of commercially brewed decaff, not make-at-home decaff. The study mentions contamination of decaff coffee with regular coffee in brewing equipment as a plausible source of the caffeine.

Section should read something like:

"Some commercially available decaffeinated coffee products contain considerable levels of caffeine. One study found decaffeinated coffee contained 10 mg of caffeine per cup, compared to approximately 85 mg of caffeine per cup for regular coffee." (talk) 15:57, 4 October 2013 (UTC)

Done, more or less as suggested. Looie496 (talk) 16:18, 4 October 2013 (UTC)

Caffeine toxicity

Recent death where caffeine is primary cause — Preceding unsigned comment added by (talk) 18:21, 11 October 2013 (UTC)

Suggested correction for 3rd paragraph

Part of the reason caffeine is classified by the Food and Drug Administration as GRAS (generally recognized as safe) is that toxic doses (over 1 gram for an average adult) are much higher than typically used doses (less than 500 milligrams).

This sentence, which begins the 3rd paragraph of the article, is misleading and could be worded better. 500 milligrams is equal to 1/2 gram. 1 gram is not a much higher dose than 1/2 gram. The typically used dose of caffeine is actually 100 milligrams or less. 1 gram is a much higher dose that 1/10 of a gram. I only suggest changing it because it snagged me as I was reading it and made stop to think about what it was saying, in a way that was "time-wasting." Better wording would make it more sensible. Such as . . .
Part of the reason caffeine is classified by the Food and Drug Administration as GRAS (generally recognized as safe) is that toxic doses (over 1 gram for an average adult) are much higher than typically used doses (less than 100 milligrams). (talk) 17:41, 25 November 2013 (UTC)Rusty Smith,

I just came here to point out the same issue. Saying that caffeine is 'safe' because a normal dose is half of a lethal dose is absurd -- that implies that one cup of coffee is safe but two cups can kill. The main issue, though, is not in the '500mg' part (which would be a big cup of coffee but not unheard of), but the 'over 1 gram' bit. If the ld50 is 192 milligrams/kilogram then the lethal dose for me (an 80kg human) would be 15 grams -- /way/ over 1 gram.Andrewbogott (talk) 18:01, 9 December 2013 (UTC)
After reading through the information in the Toxicity section, I changed the number to 10 grams. Does that seem okay? Looie496 (talk) 19:10, 9 December 2013 (UTC)
Yep, much better. Andrewbogott (talk) 05:47, 10 December 2013 (UTC)

reference link correction

Please note that has been rebranded to can you please edit our link in the reference section (#89) . new link should be (talk) 17:26, 6 December 2013 (UTC)

Done. Thanks. Rivertorch (talk) 19:13, 8 December 2013 (UTC)

Melting/Boiling Points

Correct me if I'm wrong, but the melting and boiling points seem to be switched. The melting point is listed as 235 °C and the boiling point as 178 °C.Djkauffman (talk) 19:43, 10 December 2013 (UTC)


"Part of the reason caffeine is classified by the Food and Drug Administration as GRAS (generally recognized as safe) is that toxic doses (over 10 grams for an average adult) are much higher than typically used doses (less than 500 milligrams)" This needs a citation as i doubt the committee would utter such nonsense. Toxicity, as well as beneficial effects, start with a cup of coffee, i.e. 50-100mg. Death holds out waiting for more java. — Preceding unsigned comment added by (talk) 22:49, 2 March 2014 (UTC)

Primary sources

Appears the article has been packed full of old primary sources again :-( Doc James (talk · contribs · email) (if I write on your page reply on mine) 05:00, 20 March 2014 (UTC)

IUPAC name is wrong

This article is protected so I can't change it, but the IUPAC name is wrong. It concatenates two alternative names. It should be 1,3,7-Trimethyl-1H-purine-2,6(3H,7H)-dione *or* 3,7-Dihydro-1,3,7-trimethyl-1H-purine-2,6-dione, not both. (talk) 22:15, 27 March 2014 (UTC)

'Not done: It seems clear to me that the two names listed are alternative names and not one very long one. Cannolis (talk) 12:33, 28 March 2014 (UTC)

Semi-protected edit request on 29 March 2014

Psychological effects The first sentence of the third paragraph of the "Psychological effects" section reads: "Caffeine can a negative on anxiety disorders."

Some words seem to be missing there.. I believe it was intended to read: "Caffeine can have a negative effect on anxiety disorders." (talk) 23:39, 29 March 2014 (UTC)

Done. I've restored the sentence to what it was prior to that change. @Jmh649: Can you take another look at what you were trying to do to that sentence? What ended up there didn't make any sense. --ElHef (Meep?) 23:57, 29 March 2014 (UTC)
Yes missed the "have". Fixed. Doc James (talk · contribs · email) (if I write on your page reply on mine) 04:39, 2 April 2014 (UTC)

athsma → asthma

I'd fix this typo but I can't edit the article! — Preceding unsigned comment added by (talk) 13:11, 15 April 2014 (UTC)

Difference between caffeine content in dark and light roasts

"In general, dark-roast coffee has very slightly less caffeine than lighter roasts because the roasting process reduces a small amount of the bean's caffeine content." I was looking into this, and I'm getting some differing information on the subject. Several sources are saying that it depends on how you measure it; by volume, a light roast will have more caffeine. By weight, the dark roast will have more because the roasting process has decreased its mass. It might also be worth noting that this is a small difference. I'd like to find a scientific study of the actual measurements for some verification. — Preceding unsigned comment added by (talk) 17:26, 29 April 2014 (UTC)

Edit Request: Add information on LD50 in the table at the right corner, justa like in German

Recently looked at LD50 of caffeine to assure safety on its use in higher doses. To acquire this information I had to resort to German wikipedia, as this information was not only more complete but clearly displayed at the first table in the right corner. I've got concerned with this lack of clarity as recently a few people died of caffeine overdose. Could somebody give me permission to edit this page or edit it for me? Also, why is this page protected? Diogopell (talk) 23:55, 1 July 2014 (UTC)

What do you wish to add to this page / change the text to? Doc James (talk · contribs · email) (if I write on your page reply on mine) 00:20, 2 July 2014 (UTC)

Edit request: Change incorrect information "antagonist" to "agonist"

In the Pharmacology section, "an antagonist of the ryanodine receptors (RYR1, RYR2, and RYR3)". The cited reference [116] says that caffeine is an agonist at RyRs. — Preceding unsigned comment added by (talk) 17:47, 12 February 2015 (UTC)

You have a sharp eye. Thank you: will review. This is not an area in which I have expertise, so will need to do a bit of self-education. (How did this new section get inserted between two July 2014 sections?) - IiKkEe (talk) 11:29, 18 February 2015 (UTC)
Wow! - 19 minutes after I wrote the above, Seppi333 swept in and nailed it, and with a reference: It is both an antagonist and agonist (activator). Sweet. - IiKkEe (talk) 12:15, 18 February 2015 (UTC)

Citation 169 "caffeine poisoning in dogs" is broken

Link sends me to > — Preceding unsigned comment added by (talk) 13:35, 24 July 2014 (UTC)

Broken infobox

There is an awful lot of data provided to the infobox that is not appearing on the page - safety data, CAS number, physical properties, etc. It looks like the article formerly used Template:Chembox for the infobox, which supported all the chemical data, but that template was eliminated and redirected to Template:Infobox drug, which does not support chemical data. I imagine a separate chembox would now be required to restore the missing data to the article. Not exactly as simple as a standard edit request, but would someone either refactor the unsupported infobox fields into a separate chembox or remove them to reduce the potential for confusion? (talk) 13:35, 10 August 2014 (UTC)

FixedSeppi333 (Insert  | Maintained) 17:55, 10 August 2014 (UTC)

Edit Request: Change "Expresso" to "Espresso" in the fourth paragraph

Fairly sure this is a simple misspelling. (talk) 15:32, 17 December 2014 (UTC)

Update reference

Reference [169] currently redirects to a porn site.

A replacement reference that supports the assertion "While safe in humans, caffeine is considerably more toxic to various animals, such as dogs" can be found here:

Jmh02001 (talk) 04:11, 12 September 2014 (UTC)

Thanks, fixed and welcome. Doc James (talk · contribs · email) (if I write on your page reply on mine) 07:44, 12 September 2014 (UTC)

Edit request on November, 1, 2014

Please correct the internal link where it says:

Caffeine is a receptor antagonist at all adenosine receptor subtypes (A1, A2A, A2B, and A3 receptors)."

"A1" is leading to "Alpha 1 adrenergic receptor" when it should actually link to "Adenosine A1 receptor".

Thanks. --Igorhb (talk) 16:17, 1 October 2014 (UTC)

Fixed Thanks for pointing it out. Seppi333 (Insert  | Maintained) 16:21, 16 October 2014 (UTC)

Caffeine melting point is correct in the info box, wrong in the body of the article; also sublimation point is highly misleading

There are two conflicting values given for the melting point of caffeine. The value in the info box is correct, according to the Merck Index (12th ed) and my own personal experience as an organic chemist: 235-238C. However, in the body of the article under the Chemical properties and biosynthesis section, the MP is incorrectly stated as 225-228C. I think this must be a simple typo.

Also, there is a serious error under boiling point in the info box (or a series of errors):

First, the boiling point is listed as: 178C (sublimes). First of all, the normal boiling point (the BP at 1 atm pressure) can NOT be lower than the normal melting point (the MP at 1 atm). It must be higher. There are no substances with normal boiling points lower than their normal melting points.

Second, if this is a sublimation point, it should NOT be listed under "boiling point" - sublimation is a totally different process than boiling, and the two should not be conflated. Caffeine does not have a normal boiling point because it decomposes soon after melting at around 238C.

Third, while caffeine can sublimate, it does not have a "normal sublimation point" -- that is, there is no temperature at 1 atm pressure in which the solid/gas equilibrium favors the gas phase. We know this is true because it has a normal melting point. Therefore, the triple point pressure for caffeine must be above 1 atm. If the triple point lies above 1 atm, there is no temperature at which it spontaneously sublimes at 1 atm. If you look at a phase diagram, you will see that this has to be true. Carbon dioxide's triple point is something like 5 atm, so it has a normal sublimation point (but not a normal melting point). It is impossible to have both a [normal] sublimation point and a [normal] melting point. I'm sure that caffeine sublimes at 178C at SOME pressure (below 1 atm), but it's critical to include pressure information here, otherwise it's very misleading (in the absence of pressure data, we usually assume 1 atm). So unless there is pressure data for the 178C value, that number should be removed.

Degrys (talk) 22:30, 15 October 2014 (UTC)Hans de Grys

I've fixed the MP in the body of the article, referenced the MP in the drugbox, and deleted the BP. These[1][2] were the references for those values - I've quoted them below. Seppi333 (Insert  | Maintained) 01:23, 16 October 2014 (UTC)


  1. ^ "Caffeine". Pubchem Compound. NCBI. Retrieved 16 October 2014.
    Boiling Point
    178 deg C (sublimes)
    Melting Point
    238 DEG C (ANHYD)
  2. ^ "Caffeine". ChemSpider. Royal Society of Chemistry. Retrieved 16 October 2014. Experimental Melting Point:
    234-236 °C Alfa Aesar
    237 °C Oxford University Chemical Safety Data
    238 °C LKT Labs [C0221]
    237 °C Jean-Claude Bradley Open Melting Point Dataset 14937
    238 °C Jean-Claude Bradley Open Melting Point Dataset 17008, 17229, 22105, 27892, 27893, 27894, 27895
    235.25 °C Jean-Claude Bradley Open Melting Point Dataset 27892, 27893, 27894, 27895
    236 °C Jean-Claude Bradley Open Melting Point Dataset 27892, 27893, 27894, 27895
    235 °C Jean-Claude Bradley Open Melting Point Dataset 6603
    234-236 °C Alfa Aesar A10431, 39214
    Experimental Boiling Point:
    178 °C (Sublimes) Alfa Aesar
    178 °C (Sublimes) Alfa Aesar 39214

Thanks - I've traced almost all the references I could find about the "178C sublimed" data back to the Merck Index - which does list this info, but without a pressure and without a reference. The next sentence is "Fast sublimation is obtained at 160-165C under 1 mm press." It seems dubious to me that normal sublimation (1 atm) would occur at 178C, while sublimation occurs only 13-18C cooler at 1 mm Hg. I will continue to search for primary literature about caffeine sublimation and associated pressure. Degrys (talk) 14:49, 16 October 2014 (UTC)Hans de Grys

Borked formatting

@IiKkEe: Your changes to the article lead layout violate MOS:LEAD - it should be at most 4 paragraphs. You've made it 9. One sentence paragraphs are also undesirable - it's simply bad writing. Please keep the article formatted correctly per the WP:Manual of style when you edit it. Seppi333 (Insert  | Maintained) 15:19, 9 November 2014 (UTC)

Seppi333:Thanks for educating me about the 4 paragraph limit. I have followed many of your edits on articles we were both editing in the past, and am always impressed with your contributions. On a related subject: I believe this lead is too long, it contains too much detail that is also covered in the article itself. Would you take a look at my shorter lead once I have completed some deletions, and tell me if I have removed items you believe should be retained? Thanks.

IiKkEe (talk) 23:42, 9 November 2014 (UTC)

To many issues in these edits [11]

  1. The addition of primary sources [12] when we should be using secondary sources
  2. Dependency and tolerance is not a mild overdose
  3. Not sure why "Sources and consumption" was changed to "Amount Consumed" as it also deals with sources
  4. Many of the changes made the language more complicated. For example "antagonize adenosine receptors" replaced "counteract a substance called adenosine"

Doc James (talk · contribs · email) 03:58, 10 November 2014 (UTC)

Looking at it further. Most looks good and thus restored most of it. Doc James (talk · contribs · email) 05:37, 10 November 2014 (UTC)

Fixed citation mistakes and edited a part of the lead

I fixed some errors in the citations in the lead text, then removed the statement about caffeine not causing dehydration as it is discussed in detail in the "effects on kidneys" section. The latter was probably not a constructive edit? I would love some feedback. Hvaara TC 02:29, 17 November 2014 (UTC)

Your edits in my view are spot on.

IiKkEe (talk) 15:54, 29 November 2014 (UTC)

Section headings

We have a MOS for section headings here which states "The provisions in Article titles generally apply". The recommendations for article titles are here and include:

  • "Do not use A, An, or The as the first word". The word "on" would also be included.
  • Per WP:MEDMOS we use "other animals" or "other organisms"
  • Titles should normally be noun phrases.
  • Also per here "The title is no longer than necessary"

Doc James (talk · contribs · email) 05:37, 28 November 2014 (UTC)

The metabolite theobromine

Theobromine is identified incorrectly as a vasoconstrictor in the third paragraph of this article, when it is a vasodilator. In the separate page for theobromine, it is listed as a vasodilator. Later in the article on caffeine, it is listed as a vasodilator. I can't fix this, but someone should. — Preceding unsigned comment added by Reklaws 13 (talkcontribs) 01:43, 1 December 2014 (UTC)

Thank you for pointing out my error. Have fixed.

IiKkEe (talk) 10:51, 5 December 2014 (UTC)

Section ordering

Unless there is a good reason not to we should typically follow the order of sections at WP:MEDMOS. Thus reverted [13] Doc James (talk · contribs · email) 06:41, 10 December 2014 (UTC)

Edit Request: Change "Expresso" to "Espresso" in the fourth paragraph

Fairly sure this is a simple misspelling. (talk) 15:32, 17 December 2014 (UTC)

 Done Deli nk (talk) 16:39, 17 December 2014 (UTC)
I wish I could say it was a misspell. Not being a coffee drinker, when I looked up the three methods of making coffee, I actually thought the word was "expresso". So it was a misreading on my part, not a misspelling. I thought maybe it was the fastest way! I talked to the manager of a coffee house, and he said half the people who order it pronounce it "expresso". Thanks for fixing the Page. IiKkEe (talk) 07:17, 26 December 2014 (UTC)

Does caffeine not also cause the release of dopamine?

I was under the impression (And the "Health effects of caffeine page" seems to confirm) that caffeine also indirectly caused an increase in dopamine levels in the brain, which is partially responsible for the feel-good factor from drinking coffee and other energy drinks. Is the health effects page incorrect, or should this not be included in the main page as well?

It is odd that this is not signed or dated. I have never seen an entry without those identifiers. Will look into question and add to article if verifiable.
IiKkEe (talk) 13:09, 22 December 2014 (UTC)
This section was added on Dec 20 by an IP editor -- they often are not aware of how to sign and date a comment. Anyway, caffeine via its effects on adenosine probably alters nearly everything in the brain to some degree. The question is whether its effects on dopamine have drawn substantial attention in the literature. Looie496 (talk) 17:58, 23 December 2014 (UTC)


We state "It can be used to treat asthma"

This study makes no mention of its use to treat asthma.[14] It is a total of 75 people. Its use is not mentioned in treatment guidelines as far as I am aware. It is commented on as "People may need to avoid caffeine for at least four hours prior to lung function testing, as caffeine ingestion could cause misinterpretation of the results." Doc James (talk · contribs · email) 08:45, 24 December 2014 (UTC)

Nevertheless, caffeine has the same action as theophylline, a closely related molecule,and there is evidence from many studies that it similarly relaxes airways. It's not used clinically that way, but there's not much doubt that it has somewhat the same effect. See PMID 20091514. That's probably enough for a short mention in this article, so long as it doesn't suggest that doctors use caffeine routinely as a drug for asthma. SBHarris 04:00, 25 December 2014 (UTC)
Yes it can be mentioned in the body of the article. Were I was opposed to it being mentioned was in the lead. Doc James (talk · contribs · email) 09:34, 25 December 2014 (UTC)

Citation to support statements in lead request

A cup (7 ounces) of coffee contains 80–175 mg. of caffeine, depending on what "bean" (seed) is used and how it is prepared: by drip, percolation, or espresso. I always thought there were 8 ounces in a cup but coffee is often served in smaller than 8 ounces containers, expresso in thumbnail containers. Citation please. The citation for Cardiovascular disease such as coronary artery disease and stroke is less likely with 3-5 cups of coffee per day but more likely with over 5 cups per day does not state what size cup which really makes me wonder how reliable the citation is.1archie99 (talk) 18:53, 28 December 2014 (UTC)

Both good points. I remember reading somewhere that that 7 ounces was an "official" definition of a cup of coffee, and it did not reach my consciousness at that moment that that violates the standard definition of a cup as being 8 ounces. Will look into this and alter Page as needed. Also, the citation you refer to was a meta-analysis: I will look into whether it is possible to find out whether every study analyzed defined what the size of a cup was. I suspect it was based on self-reporting via subject interviews. For now, will add a cautionary "One meta-analysis concluded...", and look into it further. Thanks for raising these questions. Regards, IiKkEe (talk) 17:31, 3 January 2015 (UTC)

Weird question in the first section

The question "How much caffeine is in your daily habit?" is just sitting in the first section without any relation to the surrounding sentences. Should probably just be removed. — Preceding unsigned comment added by (talk) 16:00, 29 December 2014 (UTC)


We have a section on sources of caffeine. Products that contain caffeine are by definition sources. Synthesis of caffeine is also a source. Thus IMO these heading should go as subheadings of sources. Doc James (talk · contribs · email) 12:54, 2 January 2015 (UTC)

User:IiKkEe I would appreciate you commenting on the talk page. Coffee and tea are biological sources. We even have a see also caffeinated drink under the previous sources heading. Doc James (talk · contribs · email) 13:12, 2 January 2015 (UTC)
Good point. I have altered TOC according to your suggestion: Sources is main topic with 3 subtopics. Looks good! Regards. IiKkEe (talk) 13:53, 2 January 2015 (UTC)
Thanks :-) Doc James (talk · contribs · email) 21:00, 2 January 2015 (UTC)

I find this source confusing. It does not list what the abbreviations in the tables are for. Perhaps we need a better citation.1archie99 (talk) 22:04, 4 January 2015 (UTC)

... Erowid isn't a suitable source for any drug article. Seppi333 (Insert  | Maintained) 06:33, 5 January 2015 (UTC)
Seconded. Perhaps we should make a bot that looks for "erowid" or "sciencemadness" between <ref> tags :)
Riventree (talk) 08:26, 19 January 2015 (UTC)

Semi-protected edit request on 12 January 2015

It is found in the seeds, nuts, or leaves of a small number of plants native to South America. The most well known source of caffeine is the seed (commonly incorrectly referred to as the "bean") of the coffea arabica coffee plant.

Becky: Page is Locked so let the wiki experts deal with it. Is this really indicative of a level-4 vital article in Science for Wikipedia? If you do not understand my comments about Caffeine being a plant based xanthine alkaloid found in OLD World and NEW World plants, then let someone else read my comments and make the changes needed to keep the article somewhat factually accurate. The caffeine entry is tiresomely verbose and factually inaccurate at the same time. Why devote a paragraph to S American sources of caffeine when Coffee and Tea are number 1 and 2 sources of this alkaloid for human commerce by more than a thousand fold over all other sources of caffeine combined. Coffee bean harvest = 6-7 Bil metric tons vs Tea 5-6 Bil metric tons harvested 2012 source: Statista top coffee producers worldwide), assuming 2% w/w caffeine content in this 2012 harvest, that is more than 120 million tons of caffeine harvested as coffee beans for 2012. And drop that oddity Coffee seed used throughout the article.

-while use of the word bean to refer to the seed of the Coffea arabica plant is botanically incorrect, it is also common English usage, just as we commonly refer to a cucumber as a vegetable and not a fruit although botanically speaking it contains seeds so is a fruit.

Multiple problems. Coffea arabica natural growth range is in Yemen, Ethiopia, not a S. American native plant although widely commercially CULTIVATED in S. America, it is not native to that continent, thereby refuting statement that it is a new world alkaloid. Camellia sinensis is the black and green tea plant and is the most widely consumed source of caffeine. Please note this plant originated in China and is not cultivated or otherwise found in S. America. Coffea and Tea are the two most widely known and consumed caffeine containing plants and NEITHER is a native to S. America, so refuting the statement that the sole source of these alkaloids is S. American vegetation.

Also note that purine metabolism in man is a complex subject and many diseases can result from metabolically damaged purine pathways including gout and others(source wikipedia page on purine metabolism Symptoms can include gout, anaemia, epilepsy, delayed development, deafness, compulsive self-biting, kidney failure or stones, or loss of immunity). This is a more important link to health related issues than pointing out that the guanine and adenine purines are found in RNA, which although true is but of little significance to understanding the role caffeine and theophylline metabolism and pharmacology play when consumed on a daily basis by much of humanity. Sweedld (talk) 05:51, 12 January 2015 (UTC)

Red question icon with gradient background.svg Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format.  B E C K Y S A Y L E 06:03, 12 January 2015 (UTC)
Red information icon with gradient background.svg Not done: please establish a consensus for this alteration before using the {{edit semi-protected}} template. Sam Sing! 21:37, 15 January 2015 (UTC)

IUPAC name question

The IUPAC name for this looks weird to me: "1,3,7-Trimethylpurine-2,6-dione". The 7 for the third methyl and the 6 for the second dione look like they're using a different coordinate system. I had expected to find them on adjacent carbons, yet they are not. If I'm counting the carbons wrong, I'm sorry, but I thought someone should double-check this.

Riventree (talk) 05:40, 14 January 2015 (UTC)

Anyone? Bueller?

Riventree (talk) 08:32, 19 January 2015 (UTC)

Semi-protected edit request on 21 January 2015

Typo in Effects -> Kidney: "airline assengers" should probably be "airline passengers" Lancer827 (talk) 19:10, 21 January 2015 (UTC)

 Done Thanks for pointing that out - Arjayay (talk) 19:13, 21 January 2015 (UTC)

Caffeine article typo

Just a minor typo in the caffeine article that I want to point out. The typo is in the first paragraph of the subheading "Undesired". Below I have highlighted it in bold as it appears in the article. "n" should read "in". That is all. Thanks.

Undesired Minor undesired symptoms from caffeine ingestion not sufficiently severe to warrant a psychiatric diagnosis are common, and include mild anxiety, jitteriness, insomnia, and interference with co-ordination in athletes.[21] The caffeine-induced disorders recognized n the "The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition American Psychiatric Association (2013).[22] (DSM-5) are: caffeine-induced anxiety disorder, caffeine-induced sleep disorder, caffeine intoxication, caffeine withdrawal and caffeine-related disorder not otherwise specified.

--Wickyyutch (talk) 23:05, 23 January 2015 (UTC)

Fixed - thanks for pointing it out. Seppi333 (Insert  | Maintained) 01:18, 29 January 2015 (UTC)

Alternative to the addiction glossary template

@Doc James: I just incorporated the associated definitions/concepts from the glossary directly into the text; I actually sort of agree with you that in this particular article, the (truncated) glossary wasn't very useful. I'd like to know how do you feel about including coverage of the addiction/dependence-related concepts in articles in this manner as opposed to transcluding {{addiction glossary}} – is it preferable to you? Seppi333 (Insert  | Maintained) 01:13, 29 January 2015 (UTC)
Mildly tangential: my talk page is probably more appropriate for this discussion, but I think John Blackburne is a dick and I don't want his 2¢. Seppi333 (Insert  | Maintained) 01:15, 29 January 2015 (UTC)

I think that is reasonable if done to a limited extent. We also need to work to write in simpler language. I have simplified some. Doc James (talk · contribs · email) 01:30, 29 January 2015 (UTC)
@Doc James: There are some articles with a transcluded glossary that I think would be just as accessible if the glossary were replaced with in-text descriptions. The only two ways that I can think of doing this are parenthetical descriptions and reference group tooltips (e.g., "note"[note 1] references), both of which I used in my recent edits in this article. I know you don't like the addiction glossary, so do you have a preference for either method if I decide to replace glossary transclusions? Seppi333 (Insert  | Maintained) 03:29, 29 January 2015 (UTC)
Prefer in-text descriptions rather than notes. Many times; however, simply a wiki link is good enough. Doc James (talk · contribs · email) 06:28, 29 January 2015 (UTC)

Pharmacology section

The issue with the pharmacology content is that there are errors in pharmacodynamics and there are literally 2 different pharmacokinetics sections in the pre-revert version: -- Seppi333 (Insert  | Maintained) 13:12, 11 February 2015 (UTC)


Guaranine redirects here, but is not explained in the article. -- Beland (talk) 22:00, 13 February 2015 (UTC)

plus Added to drugbox synonyms. Seppi333 (Insert  | Maintained) 19:43, 17 February 2015 (UTC)

Section on overdose

One sentence in the "Overdose" section reads "Though achieving lethal dose of caffeine is difficult with coffee, it is easily achieved with seventy 200 milligram caffeine pills."

I think this information is unnecessary and not encyclopedic, and therefore I suggest that it should be deleted. The number of coffee cups is much more relevant as a comparison and is already listed. Thoughts anyone?

(even if it stays I think "easily" should be edited out and the qualification "for a 70 kg person" should be added.)

Kmonkmon (talk) 05:50, 19 February 2015 (UTC)

I agree the whole sentence is inappropriate, so I have removed it. Deli nk (talk) 14:41, 19 February 2015 (UTC)
Spot on. IiKkEe (talk) 14:25, 22 February 2015 (UTC)

Inaccurate Half-Life

Under Pharmacokinetics, the half-life is stated as being "roughly 6 hours". It includes a reference to this page. However, the reference page states the half-life is 3-7 hours, which is a wide range, nothing like "roughly 6 hours".

I've been trying to find studies related to the half-life of caffeine in healthy adults. The only one I could find was this one which did detect and average of 5.7 hrs, which is roughly 6, but only has a sample size of 3 people. I can't find any documentation to support even a 3-7 hour half-life, much less a "roughly 6 hours".

Until better documentation can be provided, this should be changed either to match the cited page (3-7 hours) or removed entirely. — Preceding unsigned comment added by (talk) 14:08, 12 March 2015 (UTC) Fixed Seppi333 (Insert  | Maintained) 17:06, 12 March 2015 (UTC)

Thanks for your continued dedication to accuracy. IiKkEe (talk) 13:20, 15 March 2015 (UTC)

Semi-protected edit request on 18 March 2015

Third, caffeine can enhance the reward memory of pollinators such as honey bees, thus increasing the numbers of its progeny. This is very interesting, if true. I would like to see a citation. Rikki-Tikki-Tavi (talk) 16:45, 18 March 2015 (UTC)

The statement was added to both the lead and the main article in this diff by User:Jpgordon on 8 March 2013. As you can see from the diff, the statement was correctly referenced:-
Caffeine has also been found to enhance the reward memory of honeybees, improving the reproductive success of the plant.[1]
The article has been edited about 1200 times since then, the statement in the lead has been moved down, but the citation is still there (currently No 171) in this section - Arjayay (talk) 18:16, 18 March 2015 (UTC)


  1. ^ Wright, G.A. (2013). "Caffeine in Floral Nectar Enhances a Pollinator's Memory of Reward". Science (6124): 1202–1204.  Unknown parameter |vol= ignored (|volume= suggested) (help)

"Small number of plants native to South America"

In the Introduction it is stated that caffeine is contained in the parts of a small number of plants native to South America." This seems to suggest that caffeine is only found in South-American plants, and that the number of species of such plants is small. For the second claim (the small number) no evidence or citation is given. For the first claim, it is wrong, as the tea plant Camilla sinensis which is native to East Asia, also contains caffeine. (talk) 09:44, 13 April 2015 (UTC)

The 'Natural occurrence section' states it is found in about sixty plants. I don't believe this is a small number so I've altered the text accordingly. East Asian plants are now noted in the lead. Sizeofint (talk) 17:13, 13 April 2015 (UTC)