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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)

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)

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's Harisbhai 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.

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)

• 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)

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)

Please see the questions I asked about this image here: commons:Image_talk:Caffeinated_spiderwebs.jpg - I'm concerned about the "Noever" reference that's been given. Sorry if I'm simply overlooking something obvious. Scray ( talk) 04:11, 2 September 2008 (UTC)

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).

I will remove the following link: http://www.caffeinated.jp/ because it's broken. —Preceding unsigned comment added by 88.24.88.222 ( talk) 19:58, 8 April 2009 (UTC)

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)

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

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)

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)

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)

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)

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)

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)

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.

[unsigned]

Serotonin Syndrome

Last week I overdosed on somewhere around 1.5g of caffeine (accidental - I took 100mg every half hour over the course of the day, still tired, finally too much) - resulting in 15 hours of terror (took over 24 hours to return to normal). I have a new-found respect for the drug caffeine.

Yesterday, 8 days after the caffeine overdose, I took a single 300mg St. John's Wart (standardized), and proceeded to endure another day of terror, this time from serotonin syndrome (presumably). I had not taken St. John's Wart or any other medication since the caffeine overdose. Certainly makes for an interesting week.

This SSRI experience makes more sense of the fact that, following the caffeine overdose, after eating I would often experience a flushing sensation. The meals typically involved peanut butter, miso soup, or fish. These foods are contraindicated for users of MOAI's. (MAOI diet: http://www.dr-bob.org/tips/maoi.html)

This summarizes what I have found: "large doses of caffeine taken with antidepressants that have a serotonergic effect put patients at risk of developing the serotonin syndrome." source: http://www3.interscience.wiley.com/cgi-bin/fulltext/109087387/PDFSTART

Someone more knowledgeable than I might add to the article, explaining how large doses of caffeine can have an MAOI effect, which in combination with SSRI's can result in serotonin syndrome (possibly many days after the caffeine overdose). Also, is the MAOI diet something that should be applied to persons after experiencing a caffeine overdose?

Thanks

Exists ( talk) 03:33, 29 May 2008 (UTC)

Caffeine does NOT cause serotonin syndrome, caffeine indirectly and weakly raises dopamine levels and serotonin syndrome is not a result of dopamine. Sincerally, C6541 ( T↔ C) at 20:59, 25 June 2009 (UTC)

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)

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)

Caffeine does have a melting point. I have tried heating up pharmaceutical grade caffeine (anhydrous) in a melting point apparatus, and I saw it melt at exactly the melting point the Merck Index had. I have also tried making it sublimate, and it did this as well. The thing is that it starts sublimating at about 178c as far as I can remember, but it starts boiling later on. You can stop heating it at 178c and it will just sublimate, but if you keep heating it, it will eventually melt and start boiling.

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. – Clockwork Soul 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)

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)

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? – Clockwork Soul 15:33, 3 September 2007 (UTC)

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. – Clockwork Soul 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. – Clockwork Soul 17:22, 18 September 2007 (UTC)

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)

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).

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)

As far as i'm aware, the premise of caffeinated bathing procuts is that the caffiene produces a localised stimulant/irritant reaction on the skin surface, not that the caffeine is absorbed into the central nervous system and results in a systemic reaction or 'buzz', as these references seem to claim (the 'thinkgeek' products, which anyway seem to me to be novelty/spoof products) and then test. Xanatrilby ( talk) 13:33, 4 January 2009 (UTC)

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)

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)

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. – Clockwork Soul 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)

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)

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)

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)

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)

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)

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.

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)

Not all CNS stims are laxatives, I would imagine any smooth muscle relaxers like caffeine would be a laxative, but things like amphetamine or cocaine are not laxatives, opposites probably... Sincerely and truly yours, C6541 ( T↔ C) at 05:07, 2 January 2009 (UTC)

I'd always believed that it was the coffee creamer that worked as a laxitive. —Preceding unsigned comment added by 67.161.122.193 ( talk) 18:37, 13 April 2008 (UTC)

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

"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)

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)

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)

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)

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)

Any use of caffeine is recreational if it is not being used under any doctor's indication. Yes you are a drug abuser like the rest of drug using society if you drink that cup of joe. Sincerely and truly yours, C6541 ( T↔ C) at 05:06, 2 January 2009 (UTC)

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)

"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)

No, it's just the effects are different among individuals. There are people, who get overdose symptoms after ingesting as little as 250 mg or even less than that. It also depends on developed drug tolerance. -- 83.24.74.119 ( talk) 17:18, 2 June 2008 (UTC)

I agree that this seems dubious. I would imagine, though I am not in medicine, that one would need to be infantile to see symptoms from such a small dose of caffeine. 250 mg of caffine is less than 3-4mg/kg in an average sized individual... One starbucks venti/large/whatever coffee contains a varying amount of caffeine between 250 and 600 milligrams, according to their website, depending on how long it has been left to heat.. This would of course indicate that one cup of coffee could produce twice the overdose/intoxication level - tantamount, by some logic, to saying that a glass of beer could produce .16 blood alcohol levels (twice intoxication) in some individuals; a claim we would surely dismiss as absurd. 72.139.45.236 ( talk)

As stated above, it depends on the individual. I personally can't drink a Venti Starbucks without getting intoxication symptoms, and I'm a 200 lb guy who drinks a cup of strong coffee every morning. Looie496 ( talk) 21:18, 28 October 2008 (UTC)

it was explained to me that an overdose was when you started developing symptoms that didn't occur in a smaller quantity (for aspirin,it thins blood but an overdose may cause bleeding) this title is misleading because caffeine intoxication is a term in the DSM IV which requires I believe 400 mg. Coffeepusher ( talk) 06:45, 5 August 2009 (UTC)

The LD50 around 192 mg/kg, for an 85 kg male that is over 16000 mg of caffeine. 250 mg is nowhere close to "overdose." Acsempronio ( talk) 23:48, 28 August 2009 (UTC)

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?

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. – Clockwork Soul 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. – Clockwork Soul 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)

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/ talk edits> 23:02, 28 March 2008 (UTC)

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! – Clockwork Soul 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)

Is it intuitively obvious to chemistry types that there are C's at most vertices, and also a CH on the far left, in order to make up the C8H10N4O2 count? E.g. compare your picture with [10]. (Er, wait, that one's wrong too??? Missing 2N. Perhaps see also instead... [11] at shopping link [12]) As a layman, I couldn't figure out why the molecule count wasn't right in your version. I'm not familiar with the editing tools for images, and may still need a commons account? Plus I wonder if the diagram obeys some convention for implied C and CH. -- SportWagon ( talk) 20:03, 21 October 2008 (UTC)

The Skeletal formula article talks about this standard type of molecular diagram and what is "known but implied". DMacks ( talk) 20:12, 21 October 2008 (UTC)

Thanks. Sorry. I rather thought the answer must be "yes". Perhaps all skeletal formula diagrams should somehow direct users to that article? E.g. at all images e.g. Image:Caffeine.svg "Description" should maybe link "Chemical Structure" to Skeletal formula? (And/or equivalent links could be made around the diagram use on the referring page, without distracting experts).-- SportWagon ( talk) 20:38, 21 October 2008 (UTC)

A link from the img-description sounds like a great idea! For article content, if there's a place where the structure itself is discussed, a link could be easy to include (in body-text or image-caption). However, for infobox images, there's no good place (and that's really the only place articles about chemicals are guaranteed to have a diagram of the chemicals themselves)...no caption or descriptive text. OTOH, there are often several types of images (the "3D balls" one below the skeletal one), and we recommend to image creators to make them "oriented" the same way so everyone can see how they correspond and learn what means what. So between that and the image (which leads to its description and therefore "explains itself"), I think that's the best general guideline for this kind of thing. The WP:Chem working group is in the process of validating and upgrading the infobox content for the chemicals pages, I'll suggest this as a Best Practices for skeletal-diagram images. DMacks ( talk) 01:54, 22 October 2008 (UTC)

Searching for "formula" in this talk page finds other questions asked and answered related to confusion arising from laymen encountering the hybrid (not skeletal) formula. Perhaps the treatment in Propane is a good model, where 4 alternate depictions are given. But, in one day, I personally have gone from confusion to understanding (even before seeing it verified in those other Q/A) that the CH3 could/should be omitted from a skeletal formula. (Also, propane has better "explanations" when you hover your mouse over the diagrams (alt text?)).-- SportWagon ( talk) 17:02, 22 October 2008 (UTC)

That's news to me. I've been drinking coffe since I was 7 & I'm the the tallest woman in my extended family. —Preceding unsigned comment added by 67.161.122.193 ( talk) 18:33, 13 April 2008 (UTC)

Correlation does not mean causation. —Preceding unsigned comment added by 24.18.180.214 ( talk) 06:12, 13 March 2009 (UTC)

To much jargin to read through. Which parts mention why caffine makes some people tired? —Preceding unsigned comment added by 67.161.122.193 ( talk) 18:35, 13 April 2008 (UTC)

Apparently it doesn't make you dehydrated as commonly thought. [13]. Worth adding? - Ravedave ( talk) 02:24, 15 April 2008 (UTC)

I'm a little adverse to including conclusions drawn in a summarization of a scientific literature review. If you can get the original review article and want to cite the author's conclusions directly, that's another matter. dil ( talk) 13:22, 15 April 2008 (UTC)

You mean this one? ;) The research is hardly new, but it might be nice if worked into the prose well, and not simply tacked onto the end of some paragraph. Ref is here ^[1] for an editor's convenience. I unfortunately have to get to the lab. Stupid "real life" – Clockwork Soul 13:39, 15 April 2008 (UTC)

Seems coffee and caffeine raise insulin levels and stress hormones. Why isn't this discussed in detail? Seems like a perfect recipe for obesity, abdominal obesity and all the diseases of modern civilization.

The other thing is... caffeine is extremely addictive with a very brutal withdrawal period with lingering fatigue and depression that can last upwards of two months. No doubt most if not all of the posters here and editors are users. How can we trust essentially addicts to dissemminate accurate information about this addictive drug?

I find this really hilarious:

"This is not the only case where caffeine increases the effectiveness of a drug. Caffeine makes pain relievers 40% more effective in relieving headaches and helps the body absorb headache medications more quickly, bringing faster relief.[62] For this reason, many over-the-counter headache drugs include caffeine"

This is not the case at all in the particular case of taking an analgesic with caffeine when withdrawing from caffeine. The caffeine is relieving the headache because you are getting a fix and blunting the withdrawal period, the main effect of which is powerful headaches.

68.161.194.64 ( talk) 20:00, 28 April 2008 (UTC)

Since caffeine is linked from the thermogenics section and mentioned there, maybe is should be covered. If that is the case a distinction will have to be made as to its effects on metabolism (general metabolism of caloric intake) vs. metabolism of the caffeine itself into the body. The fact that caffeine is a well-known mild thermogenic yet it is not covered in a section entitled "metabolism" seems very confusing especially if one is looking for that information. —Preceding unsigned comment added by 219.143.157.3 ( talk) 18:19, 2 May 2008 (UTC)

I searched briefly, but wasn't able to find any references to support the assertion that caffeine alters the levels of sex hormones in men and women (it's very late though, and I'm too tired to be rigorous). This is a very high-profile article, so I thought it best to remove the entire section for now lest we see it quoted all over the Net in the next few weeks.

Through two indirect mechanisms, caffeine may increase estrogen and testosterone in men, and just estrogen in women. Its antagonist action at adenosine receptors increases levels of dopamine, which decreases levels of prolactin, which in turn increases testosterone in men and estrogen in women. It also inhibits the enzyme CYP1A2, responsible for metabolism of estrogen, thus possibly increasing estrogen in both sexes. ^{citation needed}

—Preceding unsigned comment added by ClockworkSoul ( talk • contribs) – Clockwork Soul 07:07, 4 May 2008 (UTC)

I'm tired too, so I haven't looked too hard into this, but there are many places that talk about caffeine's effects on hormones, including testosterone and estrogen, mostly saying that they inhibit their production. Try a google search for "caffeine testosterone" and "caffeine estrogen" (no quotes). I haven't checked into them thoroughly enough to see if the specific claims in this passage are backed up by any reliable sources, but my guess is they do exist, due to the volume of search results. Equazcion •✗/ C • 07:15, 4 May 2008 (UTC)

There's some evidence that caffeine elevates SHBG. This results in reduced free testosterone levels (see "SHBG levels"). —Preceding unsigned comment added by 83.24.16.72 ( talk) 10:10, 1 June 2008 (UTC)

After reading the article from top to bottom I noticed that in the religion section, while the information is fairly accurate, the sentence "These people also refrain from consuming alcoholic beverages such as wine or beer and smoking cigarettes" does not seem to be on topic, article appropriate, or have any beneficial value to this article. It reads as more of an aside than anything else. I'm suggesting that it be removed, unless someone can suggest a valid reason for it being there. Aristophrenia ( talk) 05:54, 8 May 2008 (UTC)

Hmm.. I didn't see that down there. You're right, of course. Section removed. – Clockwork Soul 07:07, 8 May 2008 (UTC)

I thought the religion section was relevant, so I put it back, minus the aside about alcohol and cigarettes (which I agree is irrelevant). Klausness ( talk) 10:15, 8 May 2008 (UTC)

With the aside about cigarettes and alcohol gone, I can agree that the religion section may be appropriate. But should it really be listed as a subcategory of 'Stereo-chemistry'(which is "The branch of chemistry concerned with the three-dimensional arrangement of atoms and molecules and the effect of this on chemical reactions")? I'm working on find a source for that section since I believe that the prohibition is slightly different in regards to the wording of what is written there(addiction versus clear state of mind or something to that affect). Aristophrenia ( talk) 13:15, 8 May 2008 (UTC)

Oh, I hadn't noticed that it was a subsection of Stereochemistry. I made it its own section. Klausness ( talk) 15:51, 8 May 2008 (UTC)

Shouldn't wikipedia aiming at using S.I. units rather than fake-imperial units? Nergaal ( talk) 10:19, 6 June 2008 (UTC)

The last section includes SI units at the end of each entry; the reasoning for using imperial units is that those would be the most commonly-encountered (such as in the case of Starbucks, which, I believe, lists its sizes in fl. oz. rather than mL– which is actually not an SI unit, but is accepted in the SI system). ~XarBioGeek ^{( talk)} 21:10, 6 June 2008 (UTC)

This article talk page was automatically added with {{ WikiProject Food and drink}} banner as it falls under Category:Food or one of its subcategories. If you find this addition an error, Kindly undo the changes and update the inappropriate categories if needed. The bot was instructed to tagg these articles upon consenus from WikiProject Food and drink. You can find the related request for tagging here . Maximum and careful attention was done to avoid any wrongly tagging any categories , but mistakes may happen... If you have concerns , please inform on the project talk page -- TinucherianBot ( talk) 06:45, 4 July 2008 (UTC)

The lead section currently says: "unlike most other psychoactive substances, it is legal and unregulated in nearly all jurisdictions."
Are we aware of any jurisdiction in which it is illegal or regulated? -- 201.17.36.246 ( talk) 20:13, 9 July 2008 (UTC)

Few comments:

• 1. Why would be needed such a column? Explain and wait for consensus. Otherwise columns in every combination of units will proliferate.
• 2. Please, don't call math what is arithmetic.
• 3. No need to divide when a simple multiplication is more direct.
• 4. Use of some 70 significant figures to later round off as done is nonsense.
• 5. Shouldn't, in relation to food, be used the FDA and EU adopted conversions of 30 ml/floz?
• 6. In such a case the conversion is effected by multiplying the values in mg/litre by 0.03 ml/floz.

Jclerman ( talk) 23:52, 11 July 2008 (UTC)

I don't understand this sentence in the context: At this point, the neuron has very little energy left for the successful firing of an action potential. the article's talking about a single molecule of ATP. Can it be clarified? delldot talk 18:21, 9 August 2008 (UTC)

"THis is not the only..." This paragraph seems to be misplaced; it has nothing to do with "Tolerance and withdrawal". But I couldn't find the appropriate place for it. Will someone please put it in the right place? I added a header to lessen confusion, but the transition phrase now doesn't make sense. 198.99.123.63 ( talk) 18:56, 9 September 2008 (UTC)

I think the section "Mechanism of action" needs clarification. Is it intended to say that the only known effect of caffeine in normal dosages is as an adenosine receptor blocker, and that the other effects (increases in dopamine, acetylcholine, etc.) are due indirectly to this? If so, perhaps this should be explicitly stated. 82.1.151.34 ( talk) 16:27, 21 September 2008 (UTC)

I would like to put forward my support for this article and give praise for those who created and edited it. Although it contains many scentific parts, they are easy to understand and well written. Maybe it could be used as some sort of example template for new users to go by? Well done. Wikisaver62 ( talk) 09:32, 8 October 2008 (UTC)

Following from my rambling on this page at Is the image of the Caffeine Molecule correct? , my recent edit demonstrated how to improve the text of the diagrams when you hover your mouse over them. Watchers of this page, please review and improve (e.g. I'm not sure "hybrid skeletal" sounds right to a chemist). You probably watchlisted it anyway, but also perhaps see Propane for my inspiration and crib-sheet. It's sort of strange that the hover text is not taken, at lesat by default, from the image page.-- SportWagon ( talk) 22:04, 22 October 2008 (UTC)

A small edit war has developed concerning caffeine levels in energy drinks. According to this source, caffeine levels vary from about 9.64 mg/oz (about 80 mg/serving) for Red Bull, to as much as 500 mg in a can of Fixx. Thus, I'm reverting back to the 80+ version. If you feel that the information is wrong, please give a source that is better. looie496 ( talk) 04:53, 6 November 2008 (UTC)

The figures given for some of the coffee-based drinks look totally wrong to me, many of them lack sources, and are mathematically suspect: 1. There is in practice no such thing as a Robusto espresso - at most you would get maybe 10-20% Robusto / Arabica mix in some Italian blends - virtually all of them are 100% Arabica (literally half the caffeine) beans. 2. There is no such thing as 150mL espresso shot. A single is 30mL; a double 60mL. 3. I don't know what a "fl. oz" equates to in metric, but I assume Starbucks would use either a single (30 mL) or more probably double (60 mL) espresso shot to create it. Even if they were using the higher caffeine content of the Robusto from (1), that suggests a ceiling of ( 200 mg / 150 mL ) * 60 mL = 80 mg; not the 200 mg claimed. 4. More realistic figures are given in the "coffee" entry of wikipedia. There are figures given at http://www.mayoclinic.com/health/caffeine/AN01211 that look a little better, (although the instant coffee is a bit misleading, since it doesn't specify how much coffee powder is added and instant coffee is usually thought to contain more caffeine for the same amount of taste, since the beans are extracted for longer, and taste gets extracted before caffeine). Perhaps the references to Starbucks could be completely done away with. It would be more meaningful for non-Americans to refer to non-proprietary drinks, eg. http://books.google.com/books?id=YdpL2YCGLVYC&pg=PA230&dq=%22caffeine+content%22#PPA327,M1

I changed the Robusto entry, because it was wrong in so many ways. I also changed the "regular coffee" entry to "instant coffee", since "regular" is pretty meaningless to me. I extrapolated these figures from the above book. —Preceding unsigned comment added by 220.244.160.212 ( talk) 23:51, 6 January 2009 (UTC)

A fluid ounce is 30 mL. It was even wikilinked prior to your changes, with previously correct equivalence to the accompanying mL values. The "regular" is in comparison to "special" things listed elsewhere...what you would have just called "coffee" before people had heard of things like "instant" and "starbucks" that have their own entries. DMacks ( talk) 03:48, 7 January 2009 (UTC)

An IP editor has changed the article to state that caffeine is not a diuretic, giving as evidence http://pt.wkhealth.com/pt/re/jhnd/abstract.00009862-200312000-00004.htm -- Caffeine ingestion and fluid balance: a review. Journal of Human Nutrition & Dietetics December 2003, 16:6. The change was made in a way that broke the grammar, though, and was followed by two other IP edits that made things even worse, so I have for the moment reverted all four edits in the hope that the question could be discussed here before any changes are made to the article. Opinions? looie496 ( talk) 17:39, 20 November 2008 (UTC)

From the ref: "A profound tolerance to the diuretic and other effects of caffeine develops, however, and the actions are much diminished in individuals who regularly consume tea or coffee." DMacks ( talk) 18:47, 20 November 2008 (UTC)

Okay, so the article actually supports "mild diuretic" as the lead currently states. It might be valid to go into more detail in the body somewhere, but it looks like the lead doesn't need to be changed. looie496 ( talk) 19:12, 20 November 2008 (UTC)

Followup: I just edited the article to use that review paper as ref for the diuretic effect, instead of coffee.org. Seems like a much better source. looie496 ( talk) 19:22, 20 November 2008 (UTC)

The references in the appendix do not work correctly. The

tag clears out the internal array of data when it is used, so the last two links do not point up correctly (I should know, seeing is I was extending the cite extension last week). By my first-glance assessment, there are three ways to fix this:

1. The easiest thing is to move appendix above the references (but this is not a good solution).
2. 'Fake' the references by putting in ^{[[[#cite_note-name-98|98]]]} (but this is very nasty and unmaintainable).
3. I could not find a parser function or extension to do this, but we need some way of passing in the appendix to a function which would parse and process it, but store the resulting wikitext and only output it later. I could not find a nice way of doing this (but I could write the extension quickly if it needs to be done and there is a reasonable chance of it actually being needed—it would only be about 25 lines of code). I would like to hear about it if there is some way of doing this already though.

— Kan8eDie ( talk) 06:09, 21 November 2008 (UTC)

The chart includes the item "Coffee, Starbucks" but it is not clear whether this means Starbucks espresso or Starbucks drip coffee. On the one hand, when most people hear "Starbucks" they think espresso, but on the other, "coffee" usually indicates drip or brew coffee. Which is it? Brentonboy ( talk) 23:07, 28 November 2008 (UTC)

I have just moved this passage from lead to body: Despite its widespread use and the conventional view that it is a safe substance, a 2008 study suggested that pregnant women who consume 200 milligrams or more of caffeine per day have about twice the miscarriage risk as women who consume none. However, another 2008 study found no correlation between miscarriage and caffeine consumption. I moved it because the sources are too weak to justify putting this in the lead -- one primary source and a newspaper article. The primary source uses a design that can only show correlation, not causation, so there is no basis for flagging this as "important" by putting it in the lead. Looie496 ( talk) 18:53, 5 January 2009 (UTC)

I agree with deemphasizing that issue. Not enough evidence no draw conclusions either way, so it just cluttered the lede. Xasodfuih ( talk) 15:19, 13 January 2009 (UTC)

How many different types of caffine are there? Is the same type of caffine used in tea and coffee? Is there more caffine in tea or coffee per cup? —Preceding unsigned comment added by 84.69.186.42 ( talk) 14:03, 13 January 2009 (UTC)

Caffeine is caffeine is caffeine, period. The article has several tables comparing amounts present in various beverages. DMacks ( talk) 14:28, 13 January 2009 (UTC)

Someone needs to recalculate this section based on the table of content values. Eg Green Tea is way off. Rjk ( talk) 15:38, 20 January 2009 (UTC)

I suggest to delete the history parts that are not related to the chemcical compound coffein, that mean everything except the two last paragraphs which describe the first synthesis, etc. A disclaimer and link to the history of coffee page is enough. This would trim the article which is too long, IMHO. Northfox ( talk) 12:04, 26 January 2009 (UTC)

I can't support this. If shortening is needed, the places where it seems to me most acceptable are the Pharmacology and Decaffeination sections. Looie496 ( talk) 17:20, 26 January 2009 (UTC)

The article's first sentence says is anthropocentrically biased. It says "Caffeine is a bitter, white crystalline xanthine alkaloid that acts as a psychoactive stimulant drug and a mild diuretic[3] in humans and animals."

(I mean, it suggests that humans are not animals)

I'm surprised to see this in a featured article, but then again, anthropocentrism is ambient in our culture.

I would have changed this myself if the article wasn't featured. 195.49.248.147 ( talk) 20:52, 27 January 2009 (UTC)

How about changing it to "... in humans and other animals." ? - 195.49.248.147 ( talk) 22:35, 27 January 2009 (UTC)

This is one of those arguments that comes up over and over again in every article where it applies, and never gets settled. Yawn. Looie496 ( talk) 04:53, 28 January 2009 (UTC)

Yup. Some of those are just editorial preferences, some of those (including this one) seem aimed at a certain meaning (how distinct humans vs animals are in context). For this case, I also prefer with "other" because we're trying to illustrate how there is not a distinction, therefore better to reinforce how they are the same. Given that this type of dispute is long-running in the world of Wikipedia, I guess there's no larger discussed consensus to use either one in general? However, for the article at hand, the content was added with "other" in March 2008, so if there's really "no consensus on which to use", then we may as well respect the original author's writing instead of preference-warring. DMacks ( talk) 05:35, 28 January 2009 (UTC)

why not cut the sentence after 'diuretic'? Then the whole issue dissolves. Plants are clearly excluded from 'psychoactivity' and they also do not need diuretics. Northfox ( talk) 07:23, 28 January 2009 (UTC)

OK So we either drop the "in humans and animals" thing alltoghether, or we change it to "in humans and other animals". I think we can take a vote on the issue. I'd personally like to go with "other", and apparently so does DMacks, and the original author as well. So far Northfox is the only one in favor of dissolving the issue. So it's 3 to 1 so far. - 195.49.248.147 ( talk) 19:11, 28 January 2009 (UTC)

I don't know if this was eventually resolved, but it seems like a bit of a pointless issue. Humans and other animals may be a bit more fitting, but I don't think saying humans and animals implies that humans aren't animals, it's just a distinction that we generally tend to make as humans. Somewhat similar to how the term "drugs and alcohol" is used despite the fact that alcohol is a drug in its own right. I'm for making that change though. Which has probably already happened given the timestamp on this discussion. I haven't checked. -- Giftiger wunsch ( talk) 02:13, 29 July 2009 (UTC)

Nice one boys; I'm on my sixth cup (of caffeinated coffee) of the day, and I'm still alive and kicking. —Preceding unsigned comment added by 62.72.110.11 ( talk) 15:56, 28 January 2009 (UTC)

Tell me how you feel when you reach 100 cups of coffee in a row, which would be equivalent to swallowing a relatively small amount of *caffeine*, which is what the article is about. -- Giftiger wunsch ( talk) 02:08, 29 July 2009 (UTC)

There are three paragraphs in the "Mechanism of action" section that refer entirely to adenosine mechanisms of secrection and action, where caffeine is not mentioned once. I know that it is important to explain "adenosine slow the neurons down, so caffeine speeds them up", but I think going into this much details about adenosine shouldn't be in an article about caffeine. Independovirus ( talk) 07:32, 29 January 2009 (UTC)

I completely agree. this section needs to be shortened severely. The rest, if not mentioned already in the adenosine article, needs to be transferred there. Also, the history section is too long and contains mostly material about cofee and not caffeine. Northfox ( talk) 12:34, 29 January 2009 (UTC)

About the adenosine material, you have a point. About the history section, there are less than two full paragraphs about coffee there, it is not "mostly material about coffee". Looie496 ( talk) 04:22, 30 January 2009 (UTC)

References 68-79 cover the section about "caffeinism" and the detrimental effects on your health of large-scale caffeine consumption. Many of these articles are from the 1980s. Is this position still widely held? I'm asking this because I've never read that the effects can be so drastic. Are we sure that this isn't a 1980s belief that is no longer widely held? Epa101 ( talk) 20:40, 4 February 2009 (UTC)

Google Scholar finds plenty of recent refs using the term 'caffeinism', so the concept still seems to be widely held, although of course it might be nice to update the "facts" using more recent reviews. Looie496 ( talk) 01:12, 5 February 2009 (UTC)

I ate 100 coffee cherries, but spit out the hard seeds.

I went to sleep anyway, two hours later.

I conclude the caffeine is all contained in the hard seeds, and not the sweet cherry meat.

Please add evidence to the contrary to the article.

In fact, any statement in the article either way would be appreciated. Jidanni ( talk) 22:59, 8 February 2009 (UTC)

WP:OR, but probably in line with known facts.

Coffee processing talks about which parts of the cherry are used to make "coffee" and which are discarded, so you can see if what you did/didn't-eat matches the part that is widely used as a caffeine source. DMacks ( talk) 23:38, 8 February 2009 (UTC)

All I read is the decaffeination process is applied after the flesh is removed. So we still don't know how much caffeine is in the flesh.

However, I have some more genuine original research for you:

1. Caffeine is meant as a pesticide: don't eat me.
2. But the sweet fruit part means: eat me, (but spit out the pits please.)

So there must not be any caffeine in the sweet fruit part, or else the plant would have a conflict of interest and probably unable to compete (in evolution)! Jidanni ( talk) 23:38, 27 February 2009 (UTC)

Ahh, now I see the difference in what you asked vs what I answered:/ There is indeed caffeine in the parts that do not get sold for coffee-making. See for example [14] [15] [16]. Regarding your other proposals, just because one wards off some organisms doesn't mean it's beneficial to ward off all of them or that a chemical offensive to some is offensive to all. It's all about controlling who eats you. Playing the devil's-advocate here, the caffeine could only be in the sweet part but only have a strong inhibition against small pests that would nibble away the whole flesh+actual seed without spreading the seed. Larger animals might eat it whole without being strongly inhibited by the caffeine (maybe they even like the buzz, whereas insects can't cope with the chemical at all?), but then eject the inner seed to propagate the plant. Course this is all idle speculation. I'm glad I'm a predator that can pay someone to get me the seeds. It's exactly the pesticide content that makes me want to consume the seed but not the flesh and prevent the plant from spreading its seeds, a perfect example of how the same chemical has contradictory effects on different species:) DMacks ( talk) 00:07, 28 February 2009 (UTC)

OK, the third item you quote seems to mention that the animals sometimes reach their caffeine limit eating the pulps they are fed... Jidanni ( talk) 06:48, 3 March 2009 (UTC)

I have edited the metabolite percentages to match the source (it doesn't equal 100% now because there are at least 17 metabolites in total) but the picture is still wrong. can someone with the appropriate skills please correct this. Triscut ( talk) 02:50, 23 February 2009 (UTC)

The whole section stating drinks with an equivalent of 200mg is uncited, and contradicts very strongly with the caffeine content shown higher up on the page. In fact green tea differs by almost double the caffeine content when compared to the above table. I am going to delete it, and if an admin disagrees they can feel free to reverse it. 24.65.95.239 ( talk) 20:45, 15 March 2009 (UTC)

Adding another high Caffeine content drink Viso which has 300mg per serving. Adding a stub link to wiki.

Someone should add a section about the use of caffeine in molecular biology as an inhibitor of DNA repair: caffeine namely both inhibits the DNA damage signaling kinases ATM and ATR and also acts in as yet uncharacterised ways on other DNA damage signalling or repair pathways. —Preceding unsigned comment added by 140.77.192.140 ( talk) 12:32, 10 April 2009 (UTC)

Occurence, 2nd paragraph: "Some yerba mate enthusiasts assert that mateine is a stereoisomer of caffeine, which would make it a different substance altogether.[14] This is not true because caffeine is an achiral molecule, and therefore has no enantiomers; nor does it have other stereoisomers."

Despite the 'some yerba mate enthusiasts' qualifier, this section still feels contradictory. Even with the citations, both sentences seem speculative. As I do not know which is correct, I don't feel justified in removing either sentence, but one of them should go, or at least be moved to another section. —Preceding unsigned comment added by 98.70.34.109 ( talk) 20:03, 24 April 2009 (UTC)

The problem may be that both are correct: it's not saying "this is true and the opposite is true", but rather "this is what some say, but here's why it is not factually correct". Both positions are cited. So we make it clear that the claim is made but it's just an extraordinary claim with no extraordinary evidence, and that is contradicted and more conventionally explanable by pretty straightforward organic chemistry and biochemistry (discussed with links to the related science articles). If it's confusing as it stands, would be great to hear some alternate wordings. DMacks ( talk) 21:20, 24 April 2009 (UTC)

At this writing, the second sentence of the lede asserts flatly that caffeine is not a diuretic, and gives three sources. Two of them do not in fact assert directly that it is not a diuretic, but only cast doubt on the claim that it is; the third ref is not available without subscription so I don't know what it says.

Further down, the article points out that theobromine is a metabolite of caffeine, and assserts that theobromine "increases urine volume", which to my unpracticed eye says that it is a diuretic.

I have no position on whether caffeine is a diuretic; I just want the article to be both internally consistent and consistent with its sources, and at present neither of those appears to be true. -- Trovatore ( talk) 21:32, 30 April 2009 (UTC)

It's amazing how much controversy this question creates. What do you think of this abstract? It seems to state the story pretty clearly even if you can't access the full paper. Looie496 ( talk) 22:06, 30 April 2009 (UTC)

Yes, that seems to be a much clearer picture. If I've understood it correctly, it actually states that caffeine is a diuretic, in sufficient doses administered to naive users, but that the effect on habituated users in ordinary doses is probably too small to contribute much to dehydration. That's clearly at variance with what the article currently states (it says flatly that "caffeine is not a diuretic", which seems to be just wrong). The article should be amended to give this more nuanced view. -- Trovatore ( talk) 22:55, 30 April 2009 (UTC)

I say go for it, if you can do it without complicating the lead too much. Looie496 ( talk) 23:13, 30 April 2009 (UTC)

Done. Maybe someone with access to the refs now numbered [8] [9] [10] might be persuaded to check whether they're appropriate for the text I now have them associated with. From memory [8] and [10] are, but that could use a re-check, and I couldn't access [9]. -- Trovatore ( talk) 07:04, 1 May 2009 (UTC)

i can't find a citation for this. i'm looking through some history databases with the term "arabian wine" and coffee. the closest thing i can find is a reference to palm wine, which is also known as arabian wine, in this document at jstor (subscription required). the reference is on page 58 of the original publication, or page 62 of the digital copy. Daiv ( talk) 05:57, 1 June 2009 (UTC)

Why is Duration of effects under Decaffeination? Should it be under pharmacology?