Talk:Caffeine

Tolerance and Withdrawal

In this section, the following is listed: "Complete tolerance to sleep disruption effects of caffeine develops after consuming 400 mg of caffeine 3 times a day for 7 days. Complete tolerance to subjective effects of caffeine was observed to develop after consuming 300 mg 3 times per day for 18 days, and possibly even earlier."

I am not sure who wrote this, but the original research that this is based on does not mention anything about "3 times a day," and as such, the entire "3 times a day" part is very confusing. Is this talking about a person who takes 400mg of caffeine each time they take it, and they take it three times per day, for a total of 1200mg in a day? No, the actual article only mentions 400mg and 300 mg, respectively, used in one day. And in fact, the research indicates that the groups this research was done on received the entire dosage in one go. It was not spread out. If it was, please show me. Otherwise, the "3 times a day" should be removed. If not removed, it should be reworded for clarity.

The research link: http://www.acnp.org/G4/GN401000165/CH161.html

--75.163.59.120 (talk) 19:34, 12 December 2007 (UTC)

History of use

Conflicting data!

"In Britain, the first coffee houses were opened in London in 1652, at St Michael's Alley, Cornhill."

"The first coffee house in Europe was opened Paris in the 1800's by an French-Armenian named Pascal. " --Jonathan Drain 03:13, 1 December 2006 (UTC)

• I just noticed that someone else has already pointed this out. Looks like I need more caffeine! --Jonathan Drain 03:16, 1 December 2006 (UTC)

Caffeine-induced Drowsiness

I've heard of cases where caffeine actually induces either mild or severe drowsiness in people who consume it. Reports about the mechanism of action vary regarding what causes it, but the most common I've heard is an enzyme deficiency. Does anybody know of any sources that study or have information on this? Kelbesque 17:58, 4 December 2006 (UTC) i read in a book by herald lamb that coffee was being used around 1530'sHarisbhai 21:28, 20 March 2007 (UTC)

This could be possible (anecdotal evidence) in someone with ADHD. 72.211.227.240 21:46, 23 June 2007 (UTC)

I believe that caffè should read café if it is meant to be French.

caffeine + metabolism

hey ho. i have a question or two regarding caffeine and metabolism. the body can obviously only absorb so much caffeine at one time, like say, nicotine. if a coffee drinker drinks coffee more slowly, are they getting more caffeine from it or giving a longer plateau of caffeinated time?

i also see down there that smoking increases the metabolism, shortening the half life of caffeine. at one point i was told that cigarettes increase the amount of caffeine the body is able to metabolism - is the case just that smoking makes the body process it faster and thus get a bigger (but faster) rush? JoeSmack ^Talk 17:54, 15 December 2006 (UTC)

Not sure on the slow and steady vs. all at once methods of drinking coffee to maximize caffeine performance. In terms of metabolism, I believe the stimulant effects of caffeine are a result of caffeine itself, not the result of one of its metabolites. The activity of CYP1A2 (the cytochrome P450 enzyme that metabolizes caffeine via dealkylation at the nitrogens as shown in the article) is enhanced by nicotine. Therefore the stimulant effects would be lessened as conversion to the metabolites and the eventual rate of clearance is increased. dil 20:55, 15 December 2006 (UTC)

In the book, The World Of Caffeine by Weinberg and Bealer, they say that "scientists are still unsure as to what degree and what respects caffeine's metabolites are responsible for its effects, although most would agree that its methylxanthine products contribute to the physical and mental stimulation which are the hallmark of caffeine consumption."Teloscientist 03:54, 7 March 2007 (UTC)

Interesting - I'd like to see a reference on that one. To quote the article as it stands now: "Once in the brain, the principal mode of action of caffeine is as an antagonist of adenosine receptors found in the brain.[31] The caffeine molecule is structurally similar to adenosine, and binds to adenosine receptors on the surface of cells without activating them (an "antagonist" mechanism of action). Therefore, caffeine acts as a competitive inhibitor. The reduction in adenosine activity results in increased activity of the neurotransmitter dopamine, largely accounting for the stimulatory effects of caffeine." dil 13:47, 7 March 2007 (UTC)

I believe the use of half life to be incorrect here. First, half life is a specific scientific term to discus the period necessary for half of a mass of substance to suffer radioactive decay. Caffiene does not have a half life in this sense, as it is not radioactive, so I believe the use of half-life to be incorrect. Further, In terms of it being metabolized by the body, this is a chemical reaction and relies very heavily on the concentrations and volumes of the various chemicals involved in the reaction. The time necessary to metabolize one half a mass of caffiene is going to be highly dependant on how much caffiene is actually present, and any time listed should be qualified with a range of mass it applies to.--Joshbw 04:56, 24 July 2007 (UTC)

Radioactive half-life is just one specific example of exponential decay, a fairly common mathematical relationship seen in many branches of science. For caffeine, we're talking about biological half-life. DMacks 06:02, 24 July 2007 (UTC)

Yes, the rate equation is dependent on the amount of the reactant present. That being said, I'd make the case that the references attached to the half-lives that you're talking about give the conditions under which those half-lives were obtained. Further, if you back up a bit to reference 25, they actually give rate constants for doses from 50 mg through 750 mg; 50 mg is fairly representative of the lower end of the per serving amounts in the table to the right, and 750 mg is well in excess of highest on the list. If you calculate the half-life range based on those rate constants, you get a range of 4.25 - 7.1 hours which is easily covered by the three ranges in the body of the work: "3–4 hours...5–10 hours...9–11 hours". To make a long story short, I don't think any changes are necessary. dil 17:34, 24 July 2007 (UTC)

Caffeine is not a diuretic, well no more than water is. See this peer reviewed published study....

Caffeine, Fluid-Electrolyte Balance, Temperature Regulation, and Exercise-Heat Tolerance

Posted 07/19/2007

Lawrence E. Armstrong; Douglas J. Casa; Carl M. Maresh; Matthew S. Ganio

http://www.medscape.com/viewarticle/559762 —Preceding unsigned comment added by 218.154.23.183 (talk) 04:43, 22 January 2008 (UTC)

Reference

• Janice C. Hallal (1986). "Caffeine: Is It Hazardous to Your Patients' Health?". The American Journal of Nursing. 86 (4): 422–425.

--Stone 09:41, 8 January 2007 (UTC)

Biosynthesis might be a good point for the biochemistry and a addition to the metabolism.

• S. S. Mösli Waldhauser, J. A. Kretschmar, T. W. Baumann (1997). "N-methyltransferase activities in caffeine biosynthesis: Biochemical characterization and time course during leaf development of Coffea arabica". Phytochemistry. 44 (5): 853–859. doi:10.1016/S0031-9422(96)00662-0.{{cite journal}}: CS1 maint: multiple names: authors list (link)
• T. Suzuki, H. Ashiharaa, G. R. Waller (1992). "Purine and purine alkaloid metabolism in Camellia and Coffea plants". Phytochemistry. 31 (8): 2575–2584. doi:10.1016/0031-9422(92)83590-U.{{cite journal}}: CS1 maint: multiple names: authors list (link)
• B. H. Schulthess, P. Morath, T. W. Baumann (1996). "Caffeine biosynthesis starts with the metabolically channelled formation of 7-methyl-XMP—A new hypothesis". Phytochemistry. 41 (1): 169–175. doi:10.1016/0031-9422(95)00586-2.{{cite journal}}: CS1 maint: multiple names: authors list (link)

--Stone 09:54, 8 January 2007 (UTC)

• H. Ashihara, A. M. Monteiro, F. M. Gillies and A. Crozier (1996). "Biosynthesis of Caffeine in Leaves of Coffee". Plant Physiology. 11 (3): 747–753. PMID 12226327.{{cite journal}}: CS1 maint: multiple names: authors list (link)

Spider-web image

I'm pretty sure this page has been vandalised with the photograph that supposedly shows a spiders web when affected by caffine - seems awfully similar to http://www.youtube.com/results?search_query=spider+drugs&search=Search which is a well known spoof. —The preceding unsigned comment was added by 124.168.197.83 (talk)

The image that is there at this time, image:Caffeinated spiderwebs.jpg, is annotated as coming from:

Noever, R., J. Cronise, and R. A. Relwani. 1995. Using spider-web patterns to determine toxicity. NASA Tech Briefs 19(4):82. Published in New Scientist magazine, 27 April 1995.

I'd be interested in seeing citations explaining the spoofy nature of this picture. DMacks 17:54, 22 January 2007 (UTC)

It could well be the case that a genuine image from a legitimate scientific study was then adapted for use by the YouTube spoofers. —Lowellian (reply) 05:30, 29 May 2007 (UTC)

Removed faulty link

I have removed a link from under "Overuse" - "excitement" was taking the user to a page on quantum mechanical excitement, which is obviously not appropriate in this context. —The preceding unsigned comment was added by 131.111.8.103 (talk) 09:16, 3 February 2007 (UTC).

Line graphic

I believe the line graphics (in addition to not showing the carbon junctions, which I believe is customary, dunno) are missing one of the hydrogen molecules, the one closest to the two nitrogen ones. Caffeine is supposed to have 10. If you look at the ball graphic, there is an additional H hanging off the center left side between two C attached to two N, that doesn't have a match on the other graphic. It would be coming off the C between the two N on the left side (Sorry about the terms, I'm not a chemist....) Sln3412 00:10, 2 March 2007 (UTC)

In skeletal formulae, hydrogen atoms bonded to carbon atoms are implicit—see Skeletal formula#Implicit carbon and hydrogen atoms. This article's formula is actually not a "proper" skeletal formula since the methyl groups are explicit, but... I hope I've answered your question :) Fvasconcellos 00:23, 2 March 2007 (UTC)

Does anyone know the difference between the CH3 symbol and the H3C? As in, why is it wrong to change them all to CH3? 198.145.85.152 22:39, 1 April 2007 (UTC)

There is no real difference, it's just that people like to right it as H3C when the bond (the line) is on the right hand side, so that it looks like it's bonding to the carbon. For example, you could write ethane as H3C-CH3 to show the C-C bond more clearly. However, CH3-CH3 is also acceptable to most people. --Itub 12:55, 2 April 2007 (UTC)

Oh, I can see how that works. Thanks!198.145.85.152 21:33, 3 April 2007 (UTC)

Archiving

Gonna off-load everything up through #Topical_caffeine unless anyone complains...all long-ended discussions that were resolved, etc. DMacks 01:24, 2 March 2007 (UTC)

Done. DMacks 19:09, 5 March 2007 (UTC)

To add to the "Caffeine content of select common food and drugs" table: Product Name: Jolt Gum Serving Size 2 pieces (4g) Caffeine / Serving: ~ 100-135mg*

• Package label claims: "2 PIECES OF JOLT GUM = 1 CUP OF COFFEE"

Also: "The recommended dose of this product contains about as much caffeine as a cup of coffee. This pack contains about as much caffeine as six cups of coffee. Not a substitute for sleep. This product is as safe as coffee or energy drinks." JungleProwler 22:39, 6 March 2007 (UTC)JungleProwler

Plants that Contain Caffeine

It says on this page that over 60 known plants contain caffeine. Can there be a list showing what plants contain it and posibly in what amounts and locations (such as leaves, bark, branches, etc....) It might be good for the article. Upon reading that line I became interested in knowing what it was in exactly, so it would probably be a good idea to put it. It would increase the depth of the article; or it could be moved to another page, if this page is thought to be too big for such content. SadanYagci 18:52, 8 March 2007 (UTC)

Chirality

The page says, "Some yerba mate enthusiasts assert that mateine is a stereoisomer of caffeine, which would make it a different substance altogether.[8] However, caffeine is an achiral molecule, and therefore has no stereoisomers."

Chirality is a type of stereoisomerism, but they are not equivalent. Caffeine and mateine may be the same molecule, but I’m pretty certain the reasoning that caffeine’s achirality proves that it has no stereoisomers is faulty. —Preceding unsigned comment added by 64.91.144.89 (talk) 03:31, 29 December 2007 (UTC)

Seconded. I'll fix it. DanielCristofani (talk) 08:55, 9 March 2008 (UTC)

Effects and Tolerance

What is meant by "subjective effects"? (in second paragraph of "Tolerance and withdrawal" section)

What does "completely tolerant to most of the effects of caffeine" mean (end of same paragraph)? Does it mean that these people are basically in the same state that they would be if they consumed no caffeine (after any relevant withdrawal period that is)? Does it mean that the effects in the "Effects when taken in moderation" no longer apply (well the ones relating to whatever doseage they are actually taking anyway)?

And some of the examples given in the "in moderation" do not seem all that moderate: reference 36 leads to info about a study involving consumming the equivalent to 10 cups of coffee in two and a half hours; and the heading that reference 37 leads to includes the words "high caffeine dose".

FrankSier 23:45, 11 March 2007 (UTC)

Wow. Does somebody think caffeine is a drug, which should be regulated like nicotine and alcohol, or even banned like cannibis, cocaine, methamphetamine, etc.? I realize that there are some (e.g. Mormons) who have always felt this way about caffeine, and I think it is ironic that the puritanical United States government has tolerated it as long as it has.Shanoman 14:36, 18 April 2007 (UTC)

There's strong evidence that caffeine tolerance is NOT mediated by an increase in adenosine receptors. [1], [2] and [3]so I'd like to remove these sentences from the article but couldn't find a decent wording... Syber 04:46, 23 April 2007 (UTC)

methyltheobromine?

I'm not a chemist, so forgive my ignorance. The info box included "methyltheobromine" as an "other name". I don't see bromine in the formula and have removed "methyltheobromine" from the info box. Please let me know if I'm wrong. Cheers, :) MikeReichold 13:32, 19 March 2007 (UTC)

Actually, theobromine is the name of a related compound which, confusingly, contains no bromine whatsoever. Follow the theobromine link for more info as to why. Fvasconcellos 13:35, 19 March 2007 (UTC)

As entheogen

Could caffeine be used as an entheogen? That is, consumed in a spiritual context like shrooms or cannabis? Not asking if it's a hallucinogen, obviously. —Preceding unsigned comment added by 67.176.14.100 (talk • contribs)

Caffeine induces anxiety. Maybe this answers your question. Samsara (talk • contribs) 23:48, 27 May 2007 (UTC)

Coca cola "Classic"

One editor suggested that the name be changed to "Coca cola"; however, the source [4] clearly indicates "Coca cola Classic" as the name, and the other source [5] lists "Coca cola" with 45mg per 12oz rather than 34mg, as currently in the article. I therefore suggest that the idea of changing the name be abandoned, even and especially if the data is based on a different, historic formulation of the drink! Samsara (talk • contribs) 16:33, 30 May 2007 (UTC)

As far as the sources state, the data in both sources comes from Coca cola, not from independent laboratories. One of the sources (second listed above) does not even clearly state this, but simply has a footnote saying "Sources: National Coffee Association, National Soft Drink Association, Tea Council of the USA, and information provided by food, beverage, and pharmaceutical companies and J.J. Barone, H.R. Roberts (1996) “Caffeine Consumption.” Food Chemistry and Toxicology, vol. 34, pp. 119-129.". Samsara (talk • contribs) 16:36, 30 May 2007 (UTC)

Effects in combination with other drugs

I have been heard that certain drugs can interfere with caffeine metabolism thereby increasing its half-life in circulation. One example cited was oral contraceptives. If this is well-documented in the medical literature it might be valuable to add to this article.

Problem in "Mechanism of Action" text

There's a discontinuity in the text here, probably due to an editing error, but I'm not an expert on the neurochemistry being discussed and so I am not sure I'm the right person to fix it:

Once in the brain, the principal mode of action of caffeine is as an antagonist of adenosine receptors found in the brain.[31] The caffeine molecule is structurally similar to adenosine, and binds to adenosine receptors on the surface of cells without activating them (an "antagonist" mechanism of action). Therefore, caffeine acts as a competitive inhibitor. The reduction in adenosine activity results in increased activity of the neurotransmitter dopamine, largely accounting for the stimulatory effects of caffeine. Caffeine can also increase levels of epinephrine/adrenaline,[32] possibly via a different mechanism. Acute usage of caffeine also increases levels of serotonin, causing positive changes in mood.

The inhibition of adenosine may be relevant in its diuretic properties. Because adenosine is known to constrict preferentially the afferent arterioles of the glomerulus, its inhibition may cause vasodilation, with an increase in renal blood flow (RBF) and glomerular filtration rate (GFR). 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 and norepinephrine/noradrenaline released via the hypothalamic-pituitary-adrenal axis.[33]

The second paragraph excerpted above introduces material about the renal pharmacology of caffeine, but then the third sentence — "This effect, called competitive inhibition..." — makes no sense at all in this context. It looks like there might have been an interpolation of the first two sentences at the wrong place, i.e. in the middle of the neurochemistry discussion. However, just moving these two sentences will still leave a discontinuity, as the next sentence introduces (de novo) the term "competitive inhibition" even though the term "competetive inhibitor" was used in the previous paragraph. Also, the second paragraph proclaims the "result" of this competive inhibition to be an increase in catecholamines released by via the HPA axis, and how this is supposed to happen is not at all made clear. The first paragraph has what seems to me a more cogent treatment of the effects of adeonsine receptor antagonism, stating that it results in an increase in dopamine activity, and furthermore that this accounts for most of the stimulant effects. Then it says that caffeine can also increase levels of catecholamines "possibly by a different mechanism".

Summary: the sentences about the diuretic effects need to be moved out of the middle of the neurochemistry discussion, and there needs to be some definitive resolution of the two paragraphs that attempt to address the effects of adenosine receptor antagonism.

Mark Lundquist 20:32, 9 June 2007 (UTC)

Sublimation and melting

Does caffeine really sublime at a much lower temperature than it melts - surely this is unusual? Or is the melting only under pressure - in which case it should be mentioned. If the values are correct then perhaps they need comment. Petermr 22:35, 14 June 2007 (UTC)

If sublimation occurs at a certain pressure, seems like it is by definition at a lower temperature than the melting point at that pressure (otherwise one would melt-then-boil, not sublimate). The mp is consistent with lit at atmosphereic pressure, but sublimation of caffine is a common undergrad lab experiment also at atmospheric pressure. Dunno what to make of this. DMacks 22:53, 14 June 2007 (UTC)

I think I had a brainstorm - neglect the comment :-) Petermr 11:36, 17 June 2007 (UTC)

Don't neglect it - if it really sublimes completely at 178 degrees centigrade, then there is no melting point! But if the vapor pressure of solid caffeine is below 1 atm at 178 degrees, then there is nothing special about that temperature. Water ice does sublime in dry air at 1 atm below its melting point. The boiling/sublimation point is the temperature at which the vapor pressure reaches 1 atm (if the pressure is not specified otherwise). Icek 19:49, 31 July 2007 (UTC)

Here are a few comments - it seems like there is no real melting point, and the melting occurs only out-of-equilibrium in a superheated solid. Icek 20:39, 31 July 2007 (UTC)

Powder

Hi, The bit about caffeine intoxication mentions using crushed caffeine tablets for snorting. IIRC many caffeine tablets contain sodium hydroxide so that it burns your nose if you do it. Pure caffeine powder is cheap and easy to obtain (eg: from ebay). bought a kilo for £35 (around $70) and it's good. Can be added to drinks, or snorted. I hear it can also be smoked, but I have never succeeded. 217.134.101.219 20:06, 28 June 2007 (UTC)

Smoking it sounds kind of dangerous. I dont think thats such a good idea. 68.220.226.141 18:36, 29 June 2007 (UTC)

Agreed. I highly recommend against abusing caffeine in this way. Doing research for this article, I ran across case study after case study of people dying - usually in a very unpleasant manner - from caffeine overdoses after doing everything from snorting purified caffeine to eating coffee grounds. – ClockworkSoul 20:03, 29 June 2007 (UTC)

Yes, caffeine at very high doses = strychnine. Tim Vickers 03:54, 1 July 2007 (UTC)

Hardly. The LD-50 for strychnine is about 10mg. LD-50 for caffeine is about 10-20 *grams*. The LD-50 for table salt is only three times higher at ~70 grams. It's the dose that makes the poison.WolfKeeper 13:56, 1 July 2007 (UTC)

Green tea

It could be added that the amount of caffeine in green tea can be reduced by putting hot water (80°C) over the tee and then throwing the water away. The water will contain most of the caffeine and this will not significantely alter the taste of the tea. Then the tee can be steeped in a hot water like normal. (german: de:Grüner_Tee#Entkoffeinierung ) --helohe (talk) 23:45, 4 August 2007 (UTC)

French and Italian words for Coffee

Excuse the primitive editing, but I noticed a seeming error in the statement of the word's origin. It states that the French word for coffee is caffè, which is, in fact the Italian word for coffee. The French is café, and your source for this fact has that term. Returnoftheavenged 12:45, 7 August 2007 (UTC)

Good catch. What you saw was a partially fixed mistake. The article used to say, "from Italian ... caffè". Yesterday someone noticed the source says "French", corrected half of the statement, but left the "caffè" part alone. I've changed it to "café", so the issue should be resolved. -- Why Not A Duck 19:30, 7 August 2007 (UTC)

English got it from French, but French got it from Italian…maybe that's what the original text meant? OTOH, Italian got it from somewhere else and so on, back to Arabic. See Coffee#Etymology for more information. DMacks 20:40, 7 August 2007 (UTC)

Yes, per the same site, "café" is itself rooted in Ottoman Turkish qahveh. Should we instead use this as the origin? – ClockworkSoul 15:33, 3 September 2007 (UTC)

Vasodilation and adenosine

The article may be entirely correct, but it seems contradictory on the surface: in the mechanism of action section, caffeine is said to act by inhibiting adenosine receptors, thus acting as an indirect vasodilator (in addition to the sympathetic vasodilation effects). However, in the withdrawal section, the disinhibition of adenosine is said to cause vasodilation. It's unclear how both inhibition and disinhibition of adenosine cause vasodilation. (Perhaps these are localized effects? If so, that could be clarified.) Twthompson 16:54, 10 August 2007 (UTC)

• Hmm... I haven't checked yet, but the disinhibition causes vasodiltaion. Specifically when a person drinks caffeine regularly, his body compensates by increasing ("upregulating") the number of adenosine receptors. This provides a degree of resistance to caffeine, but when the caffeine is no longer present the combination of extra receptors and lack of inhibition acts to increase the effect of adenosine, causing vasoconstriction and the all-too-familiar headaches. I'll check for errors and correct if necessary. – ClockworkSoul 17:09, 18 September 2007 (UTC)
  • To follow up, caffeine works as an indirect vasoconstrictor in most parts of the body (apparently, the kidney is one exception - I'm going to read the cited source more closely). The text as written is correct, but doesn't make this interaction especially clear. I'll see what I can do to clean it up. – ClockworkSoul 17:22, 18 September 2007 (UTC)

Primary source

A general question. What does this statement mean: "The world's primary source of caffeine is the coffee bean." If we know that worldwide tea is the second most consumed beverage after water, does the statement refer to the amount of caffeine that comes from coffee? I wonder if the first source listed should be tea or at least the have the wording changed to "One of the world's primary sources of caffeine is coffee." Thoughts? —Preceding unsigned comment added by 209.134.45.231 (talk • contribs) 02:26, 12 August 2007

I don't know specifically how this information was determined, but even if nearly twice as much tea as coffee were consumed, I also see that "Tea usually contains about half as much caffeine per serving as coffee". OTOH, I also don't know whether this statement means caffeine overall or just pure caffeine as a pure material. DMacks 18:53, 12 August 2007 (UTC)

What do you mean with "caffeine overall or just pure caffeine as a pure material"??? Neither tea nor coffee is pure caffeine. Icek 00:08, 13 August 2007 (UTC)

Right. I mean caffeine on its own, or "all caffeinated things together". Let's say (per original question) that most people get most of their caffeine intake from tea. However, if I go to my chemical supplier and say "give me caffeine", they give me caffeine, not a truckload of teabags. That caffeine, as itself (a pure chemical) may come from coffee. DMacks 05:58, 13 August 2007 (UTC)

Sorry for asking my silly question - now I see that your words were quite unambiguous. From the FAO: World tea production is about 3.2 million tonnes (2004), world green coffee production is 6.7 million tonnes (1998 - 2000). As the tea referred to is dried (I assume) and the coffee is not yet roasted, the primary source for overall caffeine is probably tea. Icek 19:01, 13 August 2007 (UTC)

Opening paragraph

The lead paragraph references alternate names for caffeine by origin and also that the given names are not considered valid chemical designations. Neither "fact" (the accuracy of the names or the validity of the designations) are cited and both should be. --Dante Alighieri | Talk 22:41, 13 August 2007 (UTC)

Reference - theine. Dictionary.com. Webster's Revised Unabridged Dictionary. MICRA, Inc. http://dictionary.reference.com/browse/theine (accessed: August 14, 2007). dil 12:30, 14 August 2007 (UTC)

Well, you removed the fact tag in error then, because as I stated, we still need cites for the other two names AND the "fact" that the names are not "considered valid chemical names"... --Dante Alighieri | Talk 17:46, 14 August 2007 (UTC)

That's fine. But saying that "Webster's dictionary strikes me as a weak source for detailed information about chemical composition" likewise seems a little weak to me. We're not talking about detailed information about chemical composition. If we were, I'd find chem/biochem sources to cite. Rather, we're talking about common synonyms so I cited a book dealing with language. If you want to get into weak sources, a paragraph from pdf that only has some ill-defined "advertising material" as a reference is pretty weak. dil 19:55, 20 August 2007 (UTC)

This issue has been discussed before. You can see there the evidence for the names being synonymous and that "caffine" is the official/prefered name. Not sure what specific source from that discussion would explicitly declare "caffine is the real name" or "X is a synonym". I think "valid" could be too strong here (chemically one would say caffine is the "formal" name or "preferred" name or somesuch) leaving others as synonyms that people would understand…the only risk, and what the lead seems to try to combat, is the suggestion that they are actually different from caffeine). DMacks 17:59, 14 August 2007 (UTC)

Thank you for the link. One of the sources provided ([6]) indicates that mateine and guaranine are held up as specifically NOT caffeine, so I cannot see how it could possibly serve as a support for the sentence in it's present form. I'm removing the two uncited "synonyms" as well as the reference to the validity of theine. --Dante Alighieri | Talk 18:32, 14 August 2007 (UTC)

The study tested brewed yerba mate, not mateine, and appears to have found similar effects to caffine, which is not inconsistent with mateine (if it's the active component of yerba mate) being the same a caffeine. And it studied guarana (some natural extract), not a pure "guaranine" chemical, so observing effects beyond those expected of caffine doesn't prove that those are due to the guaranine in it or that there isn't caffeine in it. However, the database search in that discussion and this one provide much support that guaranine is a synonym, and mateine appears to be a spelling variant of one. DMacks

If you have a citeable source that the synonyms are in use as such, you are (obviously) welcome to add the cited material. Nevertheless, the PDF linked seems to indicate that the terms are ALSO in use to describe purported active ingredients in Yerba Mate and Guaraná that are (again) purported to be DISTINCT from caffeine. I don't know the best way to represent the apparent dual-usage in the article, and I welcome suggestions. --Dante Alighieri | Talk 20:10, 14 August 2007 (UTC)

Here's the relevant passage from the PDF:

There seems to be some confusion, however, whether guaraná and yerba mate contain acutal caffeine, or only caffeine-like substances. Most advertising material reports that these herbs contain substances with similar chemical constiuency to caffeine, referred to as mateine (Mowrey, n.d.), and guaranine ('Guaraná', n.d.), but that the active ingredient is not caffeine.

--Dante Alighieri | Talk 20:17, 14 August 2007 (UTC)

Oops, my "this one" link above was broken. I just repeated the PubSchem substance search for "guaranine" and got caffeine as the result. So we have a fairly authoritative source saying that the chemical called "guaranine" is a synonym for the chemical formally called "caffeine". No ambiguity about formulations, etc. Here's the results I got [7], but these URLs don't seem especially stable. DMacks 21:09, 14 August 2007 (UTC)

If the links aren't stable, we should just reference the database and not provide a link. I still think that there ought to be some mention that mateine and guaranine are also used as terms (maybe trade names?) for active ingredients in the respective products that are purported to be distinct from caffeine... but I won't lose any sleep over it. :) --Dante Alighieri | Talk 22:34, 14 August 2007 (UTC)

The synonymia has been discussed extensively also in the guarana article. PubChemId Plus and Lite are the official nomenclatre sources for all chemicals and any browser will find them; other chemical databases were extensively cited in old versions of the guarana article; mateina is the Spanish name corresponding to mateine: (Jclerman 08:19, 21 August 2007 (UTC))

• MeSH Heading

Caffeine

Name of Substance

1H-Purine-2,6-dione, 3,7-dihydro-1,3,7-trimethyl-
3,7-Dihydro-1,3,7-trimethyl-1H-purine-2,6-dione
Caffeine
Caffeine [BAN:JAN]

Synonyms

1,3,7-Trimethyl-2,6-dioxopurine
1,3,7-Trimethylxanthine
1H-Purine-2,6-dione, 3,7-dihydro-1,3,7-trimethyl-
3,7-Dihydro-1,3,7-trimethyl-1H-purine-2,6-dione
5-26-13-00558 (Beilstein Handbook Reference)
AI3-20154
Alert-pep
Anhydrous caffeine
BRN 0017705
CCRIS 1314
Cafamil
Cafecon
Cafeina
Caffedrine
Caffein
Caffeina [Italian]
Caffeine
Caffeine (natural)
Caffeine, anhydrous
Caffeine, synthetic
Caffine
Cafipel
Coffein [German]
Coffeine
Coffeinum
Dexitac
EINECS 200-362-1
Eldiatric C
FEMA No. 2224
Guaranine
HSDB 36
Hycomine
Kofein [Czech]
Koffein
Koffein [German]
Mateina
Methyltheobromide
Methyltheobromine
Methylxanthine theophylline
NCI-C02733
NO-Doz
NSC 5036
Nix Nap
Nodaca
Organex
Quick-Pep
Refresh'N
Stim
Thein
Theine
Theobromine, 1-methyl-
Theophylline, 7-methyl
Tirend
Vivarin
Xanthine, 1,3,7-trimethyl

Systematic Name

1H-Purine-2,6-dione, 3,7-dihydro-1,3,7-trimethyl-
Caffeine

Superlist Name

Caffeine

U.S. National Library of Medicine, 8600 Rockville Pike, Bethesda, MD 20894, National Institutes of Health, Department of Health & Human Services Copyright and Privacy Policy, Freedom of Information Act, Accessibility Customer Service: tehip@teh.nlm.nih.gov. —The preceding unsigned comment was added by Jclerman (talk • contribs) 08:14, August 21, 2007 (UTC).

Caffeinated Bathing Products

The article seems to be lacking information about caffeinated bathing products ( 1, 2, 3 ) and criticism they have received ( 4, 5, 6 ). --Easyas12c 11:26, 19 August 2007 (UTC)

Overuse

I've added calls for citations in the overuse section. Unlike the tolerance/withdrawal section, the claims here are a little sketchy.

The term "caffeineism" isn't defined in either of the sources that are cited thereafter. It definitely needs a source.

It's unclear why "caffeine dependency" is in quotes - are they intended to be scare quotes? The http://www.minddisorders.com/Br-Del/Caffeine-related-disorders.html source that's cited actually details that there's debate and uncertainty over whether the term "substance dependency" can be applied to caffeine at all. Without a source asserting clearly that it can, this section could use some cleanup. Tofof 00:31, 2 September 2007 (UTC)

Metabolism of Caffeine in Plants

Is there anything to be said regarding plants that make caffeine ability to use it as a reversible store of Nitrogen. How do non-caffeine producing plants react to caffeine, and metabolise caffeine. Can caffeine be absorbed by roots? 71.114.163.55 —Preceding signed but undated comment was added at 19:33, 24 September 2007 (UTC)

Relative content

The table in appendix A is interesting - however it fails to take account of either the caffeine-like substances contained in chocolate, which obviously boost the "caffeine effect" of chocolate very considerably (as any "chocoholic" will recognise) - and the fact that the strength of brew of tea has a very great influence on the amount of caffeine in it (any non-American who has ever made a cup of tea for an American will know all about that!!). I have added a note to this effect - although it is in a way subjective and POV??? Soundofmusicals 06:34, 26 September 2007 (UTC)

• Hmm... though I can't disagree with you at all, the addition does have the slightly awkward feel of editorializing. I haven't decided whether to remove it, but I'm leaning towards yes. – ClockworkSoul 17:40, 2 October 2007 (UTC)

I tend to agree about my original note - although its present form, which someone has changed, is much better. I'd leave it now. Soundofmusicals 00:16, 3 October 2007 (UTC)

caffein in tea

just how much caffein does one get from tea and what amounts can lead to dependency? —Preceding unsigned comment added by Chenjeri (talk • contribs) 02:37, 27 September 2007 (UTC)

There are several places in the article where you can learn exactly how much caffeine is in a cup of tea. There's also a whole section entitled "Tolerance and withdrawal", the first of several to address dependency issues. DMacks 02:52, 27 September 2007 (UTC)

The main point is that it varies tremendously - strong tea, as traditionally drunk in (say) Ireland may have as much as five times as much caffeine as weak tea, as typically drunk in North America. The whole question of "how much caffeine in a cup of tea (or for that matter of coffee)" is VERY problematic. How big is the cup, what is the variety of the tea (or coffee!) involved, and how long has it been steeped? SO the only answer to the original question one can possibly give is "that depends"!!!Soundofmusicals 04:59, 27 September 2007 (UTC)

I wish We Could Add to this Page

The following should be added to the Caffeine Equivalents chart: "One 6 fluid ounce cup of regular Espresso coffee (355 millilitres)" Or "Two 3 fluid ounce cups of regular Espresso coffee (355 millilitres)" As is stated in the Espresso article. And "Two 8 fluid ounce cups of regular coffee (470 millilitres)" instead of "containers" since 8 fl oz = 1 cup. —Preceding unsigned comment added by Lturcoklyl (talk • contribs) 07:53, 29 September 2007 (UTC)

Legality

caffeine is certainly an addictive drug that has toxicity above illegal ones such as THC, and even way more than heroin if isolated in pure form. what factor made it unusually easy to access and virtually no law is made against it? If it keeps people awake and increases productivity (I confess that this happens to me and myself has more or less dependency on it), amphetamine does it too. I am against drug prohibition in general and thankful to the fact that there is this legal drug, but just wonder what's the reason that caffeine is both legally and socially tolerated way much more than other psychoactive drugs, legal or illegal? Wooyi^{Talk to me?} 16:36, 29 September 2007 (UTC)

"Toxicity above illegal ones such as THC, and even way more than heroin if isolated in pure form"???? That, frankly, I very much doubt. THC and Opiates probably kill more people by accentuating any tendency their users might have to the often fatal mental diseases of paranoia and schizophrenia than as a direct result of their actual toxicity anyway. If you are sincere in your concern - then give up caffeine (I gather than is in fact MOST unlikely??) More seriously - try to imagine the social disruption, health issues, and deaths that would result if smoking pot or taking heroin became as widespread as drinking tea and coffee! Your argument (for making pot and heroin legal) is a better one when applied to alcohol - but then again, look at the social problems, disease, and death that IS caused by that drug and compare it with tea and coffee (oh, and Coca-Cola, of course). Anyway - the short answer to your question (what's the reason that caffeine is both legally and socially tolerated way much more than other psychoactive drugs, legal or illegal?)) is probably just - because it is fairly benign - and a large majority of the world's human population consume it daily with absolutely no ill-effects whatever. Good enough a reason for me! Soundofmusicals 07:13, 30 September 2007 (UTC)

I think that custom and practice make it legal. It is way more popular than alcohol and nicotine, all of which are more popular than illegal drugs. (If caffein lost its popularity, it could become illegal.) It is surprising though that soft drink manufacturers are allowed to add an addictive drug to a product sold to children. --74.15.53.217 07:03, 22 October 2007 (UTC)

It is legal because, for a start, there is absolutely no way that caffeine can be removed from all food/drink since it is so common. It will not be possible to even consider making it illegal. It is socially tolerated because, in my experience as a student in college, it is good for working and attention, and it reduces tiredness so it enhances social interaction and understanding. I, myself am dyslexic and have a very bad attention span and working memory. I find that a cup of tea in the morning makes a significant difference to my performance.

The term "addiction" is an exaggeration in this sense; in my experience, caffeine can produce withdrawal symptoms no worse than a headache. It's not the kind of addiction (I imagine) you'd get from cocaine use, which I have read from the wikipedia page, is basically 'very bad'. Don't even get me started on the toxicity; THC is not less toxic than caffeine (you can take my word for that), and since when has caffeine ever been used in pure form? Yes it is extremely toxic, but no-one considers such a ridiculous situation; it's like saying a pint of pure alcohol is much more toxic than a pint of 5% lager - of course it is. It is diluted into drinks in tiny amounts, by the order of milligrams. Adamd1008 (talk) 00:49, 26 January 2008 (UTC)

THC most certainly is less toxic than caffeine, if you go by the primary test of toxicity, LD50. While THC has an LD50 of 1270 mg/kg (male rats) and 730 mg/kg (female rats), caffeine has an LD50 of 192 mg/kg (rat). It is not you who decides toxicity. —Preceding unsigned comment added by 24.239.65.33 (talk) 20:32, 21 March 2008 (UTC)

The world's most popular psychoactive substance?

This assertion needs to be qualified. Most popular according to which criterion? The article has the following sentence: "Today, global consumption of caffeine has been estimated at 120,000 tons per annum,[25] making it the world's most popular psychoactive substance". Since the assertion in question is part of a sentence that mentions annual consumption by mass, the reader could assume that the criterion is indeed "mass consumed per year". But even a cursory look at articles on beer and wine will show that this is not possible. Based on these two articles, I estimate that annual consumption of ethanol is about 5 million tons from beer and 2 million tons from wine (and probably a few more million tons from other beverages). The total is roughly 100 times larger than for caffeine. Of course, one "dose" of caffeine is much smaller than one dose of alcohol, caffeine being measured in milligrams while alcohol is measured in grams, so perhaps caffeine is "more popular by number of 'doses'". In any case this should be clarified and better sources found if possible. --Itub 15:39, 8 October 2007 (UTC)

Artificial caffeine

Does anyone know where the caffein in soft drinks comes from? I know that some of it is extracted when decaf is made, but people drink a lot more caffeinated soft drinks than decaffeinated coffee and tea. I cannot find anything about this. --74.15.53.217 07:08, 22 October 2007 (UTC)

Unless required to be natural, it is synthetic caffeine. Jclerman 09:25, 22 October 2007 (UTC)

It would be interesting to know how the synthetic caffeine is made, and in what quantities. Do you have any idea? --Itub 10:44, 22 October 2007 (UTC)

Isn't it described in your many chemistry sources? Also search for it in a good encyclopaedia. A good start might be here [8] Jclerman 15:16, 22 October 2007 (UTC)

No, that's why I ask. I already searched the two major chemical technology encyclopedias and they didn't give much detail about this. Britannica doesn't say anything either. The best I could find was an old book in google books that says that it can be made from uric acid, but I don't know if this is still valid today. I'm especially interested in how much is extracted from coffee or other natural sources vs how much is synthesized. --Itub 15:30, 22 October 2007 (UTC)

I wouldn't be surprised if many of the modern commercial methods are patented or trade-secret. There's a 2003 journal article about a uracil-based route, which references a 1900 article about related syntheses. DMacks 16:36, 22 October 2007 (UTC)

Add guarana as a major source (I am guessing) and perhaps yerba mate. I'm not a chemist, but a physicist, so I can't help with info about the synthesis pathways. What I do know for sure is that a manufacturer of a cola, in Europe in the late 60s, in a country that stipulated that the caffeine (or the cola?) had to be natural was sending samples to determine if the thing was natural. Some samples were depleted from radiocarbon, so it was originating from petroleum or coal. Other samples were from plants grown in the N or S Hemispheres. I don't recall the C-13 values. [These methods later evolved to achieve the doping while biking fame.] The sharp N and S peaks and their decay allowed to make the fine distinction. The radiocarbon article shows these curves. We were researching 2000 yrs of atmospheric isotopes of later global climate fame. The caffeine analyses were a side-line. BTW, try to do a Google search of patents. Jclerman 20:38, 22 October 2007 (UTC)

Mentioned in DSM IV

Caffeine intoxication is very clearly noted in DSM IV and someone who contributed to the main article had obviously read DSM IV but there have been many other myths and such mixed into the passage and the entire main article making it difficult for a passing reader to differentiate between what is true and what isn't. Practically all of the section in the main article about caffeine intoxication is taken from DSM IV although it is important to note that intoxication starts from 100mg caffeine per day, not the specified 400mg; also irritability, depression, lapses in judgment, disorientation, loss of social inhibition, delusions, hallucinations, psychosis, rhabdomyolysis and death are all made up symptoms. Also for some of the more worrying real symptoms the user must take caffeine on a long-term basis. However one can become resistant to all caffeine intoxication side effects as the body becomes resistant/compensates in certain areas for the caffeine so side effects from caffeine intoxication are more severe in irregular users so some may debate that taking high levels of caffeine on a regular basis is better for you than taking any amount occasionally.

Caffeine withdrawals are a serious concern to regular users though, the side effects from withdrawal are quite unpleasant and theoretically if the body has allowed for the effects of caffeine then there is a risk that opposite symptoms may occur, e.g. Tiredness, slow thoughts, less frequent urination, lower physical performance, etc.

Laxative Effect?

Does caffiene really have a laxative effect or is this just a myth? If it does I think it'd be worth a mention in this article.--218.153.87.138 10:54, 8 November 2007 (UTC)

Yes, like all CNS stimulents it does. Ranunculoid (talk) 19:08, 7 December 2007 (UTC)

baldness

The baldness treatment article says that caffeine can be used as treatment? 132.205.44.5 (talk) 01:15, 27 November 2007 (UTC)

Half-life

"In healthy adults, caffeine's half-life is approximately 3–4 hours."

Reference(s)?? I've found articles elsewhere online saying the half-life is around 6 hours (e.g. http://science.howstuffworks.com/question5311.htm). 81.104.186.166 17:38, 1 December 2007 (UTC)

I think it varies, another place I found said 3-5, I don't consider that 6 hour necessarily very reliable, we need a reliable measured, published, experiment to change the text I think.- WolfKeeper (Talk) 18:27, 1 December 2007 (UTC)

If you scroll up to section 3 [9], the half life can vary over an ever wider range than 3-4 or 3-6 hours. Based on one of the references from the article, it was primarily based on the amount of caffeine ingested. dil 15:38, 2 December 2007 (UTC)

So did find that rather than caffeine having a half life, the body clears a certain number of mg/hour? Or something in between the two? Or what? Ben Aveling 05:32, 9 March 2008 (UTC)

The half-life is based on the amount consumed. The references I mentioned above (click the link in my last reply in this section) show it more clearly than I can by retyping it. dil (talk) 17:18, 10 April 2008 (UTC)

Structural formula

One of the hydrogen atoms (far left) is not shown in the structural formula. I think it is a bit unfortunate to show a hybrid between explicit formula and skeletal formula in this way. --Etxrge (talk) 11:54, 21 December 2007 (UTC)

From what I've seen, it's pretty standard for semi-skeletal formulas to be used; the only parts that are rarely shown as a complete skeletal are the methyl groups, which are typically represented by the CH3 that's used in the formula. The only place I've seen methyl groups represented completely skeletally is in simple hydrocarbons, such as "toluene" or methylbenzene. Then again, the most advanced chemistry qualification that I have is an AP chemistry class and some spare time spent looking and building models of organic molecules, so "what I've seen" should be taken at face value (as I see you're an engineer). XarBiogeek (talk) 00:01, 4 January 2008 (UTC)

SHBG levels

The article is protected from editing by guests, so I couldn't add this myself, bet there's something interesting about caffeine and it's effect on testosterone.

Caffeine elevates SHBG. This results in reduced free testosterone levels.

Source: American Journal of Epidemiology (144:642-44, 1996)

Regards, --83.24.45.122 (talk) 03:41, 27 December 2007 (UTC)

Uncited caffeine soap

Here is something from CNN about caffeine soap. It's just a transcript, but it is CNN. 212.179.71.70 (talk) 10:37, 31 December 2007 (UTC)

Use of caffeine pills as a recreational drug

This seems to be becoming more and more popular (although I haven't exactly been keeping tabs on it, it could've very well been just as popular twenty years ago), and I think it should be mentioned in the article. The people I know who do this generally take two, three, four or in one case seventeen caffeine pills at a time, and oftentimes do not wait the recommended amount of time before taking more. It's usually used in combination with other drugs (marijuana, alcohol), mainly to keep one from "crashing." 70.49.132.93 (talk) 16:36, 2 January 2008 (UTC)

Use as a laxative?

I added (with a reference):

Caffeine relaxes the internal anal sphincter muscles, causing a laxative effect and thus should be avoided by those with incontinence.

I'm aware of people using it deliberately as a laxative (e.g. by drinking tea - although they may not be aware that it's the caffeine giving the effect). I didn't see a notable reference on this. Someone please add if you find one. --Chriswaterguy talk 03:55, 7 February 2008 (UTC)

Caffeine intoxication

"An acute overdose of caffeine, usually in excess of 250 milligrams"

I dont understand how an acute overdose of caffeine can be 250mg as stated in this article. Further up the same page, the article states that strong caffeine pills contain 200mg of Caffeine. Thus someone taking two strong caffeine pills will have had a caffeine overdose? Or, Jolt Cola has apparently 150mg of Caffeine. Thus making two cans of Jolt an overdose. When I was at college I would regularly have three of more cans of Jolt in a row without any ill effects. I think this must be a type error and it should say 250 millgrams per body weight in kg, for example. —Preceding unsigned comment added by 69.38.135.218 (talk) 20:21, 5 March 2008 (UTC)

Occurrence

The "Occurrence" section currently says, in part

In general, one serving of coffee ranges from 40 milligrams, for a single shot (30 milliliters) of arabica-variety espresso, to about 100 milligrams for a cup (120 milliliters) of drip coffee. Generally...

Tea is another common source of caffeine. Tea usually contains about half as much caffeine per serving as coffee, depending on ...

That's not a great way of saying how much is in tea. Are we trying to say that Tea ranges from 20 mg to 50 mg? If so, then we should probably say exactly that.

Perhaps a table would be in order, with a range for each substance?

Source	mg of Caffeine	Serving Size
arabica-variety espresso coffee	40 mg	single shot (30 milliliters)
drip coffee	100 mg	a cup (120 milliliters)
decafinated coffee	?? mg	a cup (120 milliliters)
ordinary western tea	20 to 50mg	a cup
oolong tea	???	a cup
(cola based?) softdrink	10 to 50 mg	???
energy drinks	80 mg	???
chocolate	?? mg	50 g?

Regards, Ben Aveling 05:42, 9 March 2008 (UTC)

In what way would it be different from the table entitled "Caffeine content of select common food and drugs"? The table is a little further down because it doesn't fit in that section, I'm afraid. – ClockworkSoul 13:02, 9 March 2008 (UTC)

It would be possible to find without having to read the whole article?  :-) You're right that I didn't see the table - and I did look. Why do you say that a table showing the amount of caffeine occurring in various substances doesn't fit under Occurrence? It seems like a good fit to me, certainly better having it under than "Tolerance and withdrawal". Regards, Ben Aveling 22:06, 9 March 2008 (UTC)

I believe ClockworkSoul meant that it didn't fit, spatially (the table is too big to fit in the section without disrupting the other sections or leaving a gap). ~XarBioGeek ^(talk) 22:12, 9 March 2008 (UTC)

Sorry, I should have been more specific. Yes, the table is simply too large to fit there as things currently are. I'll see what I can do to, though: I might be able to shoehorn it in. – ClockworkSoul 01:57, 10 March 2008 (UTC)

Ah, I see. What about a short list under occurances, containing just the most common sources of caffeine. And a note, saying "see Appendix A for a longer list"? Cheers, Ben Aveling 09:04, 10 March 2008 (UTC)

Valuts of Erowid

This is most certainly not a reliable source; it has no established reputation for fact-checking and accuracy. I have removed one claim (caffeine not solely responsible for gastric ulcers, since decaffeinated coffee also irritates the stomach lining) and properly sourced another (ld50 in rats.) Please do not re-add Erowid for any purpose. <eleland/talkedits> 23:02, 28 March 2008 (UTC)

Is the image of the Caffeine Molecule correct?

The image of the caffeine molecule on the page is different from the one on this shirt. Which one is the correct one? -- AS Artimour (talk) 21:01, 7 April 2008 (UTC)

Isn't one just rotated 180° from the other? What difference were you noticing? DMacks (talk) 21:23, 7 April 2008 (UTC)

They are the same molecule in two different orientations, but both correct. Take either one, and flip them on the X and Y axes, and there you go! – ClockworkSoul 06:15, 8 April 2008 (UTC)

Aren't the places of H₃C and CH₃ switched on the shirt? I knew about the rotation already though. -- AS Artimour (talk) 19:00, 9 April 2008 (UTC)

The direction of writing the methyl group (H₃C and CH₃) makes no difference to the identity of the molecule depicted. You just write H₃C if carbon is bonded to something to its right.

The two depictions (t-shirt and article) represent the same molecule.

Ben (talk) 19:17, 9 April 2008 (UTC)

Stunted Growth?

That's news to me. I've been drinking coffe since I was 7 & I'm the the tallest woman in my extended family.