Talk:Caffeine

"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.

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)

WP:MEDRS

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 74.128.56.194 (talk) 00:37, 5 June 2011 (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)

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. www.xocoatl.org/caffeine.htm message.snopes.com › Urban Legends › Food digg.com/news/story/Chocolate_Does_Not_Contain_Caffeine_2 — Preceding unsigned comment added by 67.142.163.26 (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)

WP:MEDRS

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. 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. In one study, caffeinated cola has been linked to hyperactivity in children.

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

This extensive article does not comment on it at all [1] 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)

Chembox

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 pK_a. 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)

Chemistry

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; Ach, Lorenz (1895). "Neue Synthese der Harnsäure und ihrer Methylderivate". Berichte der Deutschen Chemischen Gesellschaft 28 (3): 2473–2480. doi:10.1002/cber.18950280329.  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)

Sections

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)

Alcohol

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)

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)

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 128.164.87.219 (talk) 23:06, 7 November 2011 (UTC)

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

Contreversy

Add a controversy section--88.111.116.197 (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 (talk • contribs) 03:39, 30 November 2011 (UTC)

Emil Fischer vs Herman Emil Fischer

I am the boyfriend of the widow of Gerhard Fischer who was the grandson of Hermann Emil Fischer. Overall I found the Caffeine article to be well done, but I found the references to Emil Fischer and Herman Emil Fischer confusing as they are the same person.

I don't know what the Wikipedia conventions are for hypertext URL's but it would be less confusing if you changed both the references to "Emil Fischer" as the father had a son Hermann who was a chemist of some note (headed the Chem dept at UC Berkeley, ...).

I don't get into Wikipedia discussions on a regular basis so if their is to be any further communication with me, use my email: steve at Jasik.com 71.139.177.204 (talk) 07:45, 19 December 2011 (UTC) Dec 18,2011 11.44PM PST

Suggesting a sub-topic, Regulation / Legality

One area I would be curious to see addressed is the regulation of caffeine. I suspect that USA's FDA considers caffeine sold as a CNS stimulant as an over the counter (non-prescription) drug. Similarly if included as an ingredient in nutritional supplements it would fall under USA's Dietary Supplement Health and Education Act of 1994 regulation. From an international perspective I'm also curious if regulations exist that are encyclopedic in value. 67.167.106.3 (talk) 14:17, 3 January 2012 (UTC)

Caffeine does NOT absorb dermally

The best study showed 10% absorption in after 4 hours of continuous exposure. Any mammal which possesses a stratum comeum will not absorb caffeine anywhere near as readily as a PRODUCT ADVERTISEMENT would suggest. I found it so bizarre to see the claim in the routes section, I would have been remissed not to check whether I or my beloved Wiki had broken free from reality. When I saw the Ars Technica link, I was pretty sure I was right. However, being especially nerdy, I went ahead and tried to find any ACTUAL studies, which brought me to Erowid, which has the same fact density as many parts of Wikipedia. What does that really say? Anyhum, that brings me to:

Robert L. Bronaugh, Raymond F. Stewart, Elaine R Congdon, and Albert L. Giles, Jr., "Methods of in Vitro Percutaneous Absorption Studies. I. Comparison with in Vivo Results," Toxicology and Applied Pharmacology 62: 474-480 (1982) by way of Leslie K. L. Au, M. Sc., Toxicologist at HEER, in a letter addressed to Mr. Sydney Ross Singer, Medical Anthropologist, on the subject of poisoning through the skin after the latter took to a scare from interpreting then recent studies about amphibian absorption of potentially toxic chemicals in their aquatic environment. The actual study itself seems to remain un-webbified, but considering the technical information involved and the person what got the smack down put upon them actually published it themselves, all before the shock soap bs, I feel confident citing both.

173.242.89.38 (talk) 04:47, 13 February 2012 (UTC) EAZen, never logged in, but just as annoying

Chemical structure

I generally suck at chemistry, but I am curious about something. Caffeine is C8 H10 N4 02. but in the image of the chemical structure, I only count 3 carbons and 9 hydrogens. I fully expect someone who understands chemistry to sigh exasperatedly at this question, but I'm just really curious: what gives? ~ PHDrillSergeant...§ 19:35, 20 February 2012 (UTC)

See skeletal structure. DMacks (talk) 19:37, 20 February 2012 (UTC)

Aha! I see! Of course I still suck at chemistry but at least I know I'm not going crazy or losing the ability to count! ~ PHDrillSergeant...§ 14:30, 21 February 2012 (UTC)