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Tryptophan appears to be sort-of legal now. See the following for details:

According to this page, there is about 320 mg per 3.5 oz of turkey. It also says there is about the same amount in chicken and ground beef.

tryptophan regulation pathways[edit]

Could someone put in information about the three modes of tryptophan regulation in prokaryotes? 13:11, 14 December 2006 (UTC)

I would be able to write some stuff about the trpR repressor and the attenuation mechanism, but this is briefly covered in the article attenuator (genetics). This is from personal knowledge, so it would take me a while to find the references which I don't have time to do right now, but let me know. Tapeworm87 12:19, 27 May 2007 (UTC)

makes no sense?[edit]

This statement from the article, "It is especially plentiful in turkey but only in large amounts.", makes no sense. 02:07, 19 November 2006 (UTC)

I edited something in the pop culture section. The turkey link was referring to the country of Turkey. Fixed.

The section about tryptophan and turkey previously said there was some tryptophan -> niacin -> serotonin pathway. This is wrong. The correct pathway is tryptophan -> 5-HTP -> serotonin. See the serotonin article. Simonster 05:57, 8 January 2006 (UTC)

makes no sense 2?[edit]

I find this statement from the article obscure:

Clinical research has shown mixed results with respect to tryptophan's effectiveness as a sleep aid, especially in normal patients[21][22][23] and for a growing variety of other conditions typically associated with low serotonin levels or activity in the brain[24] such as premenstrual dysphoric disorder [25] and seasonal affective disorder.[26][27] In particular, tryptophan has been showing considerable promise as an antidepressant alone,[28] and as an "augmenter" of antidepressant drugs.[28][29]

The long first sentence with all the commas, "and", "such as" & "and" again, then the switch in the next sentence to "showing considerable promise" via "in particular" leaves too much in the the shadows. Catch my drift here?

Could the effects for each and every disorder named be made more clear? For instance, by using more and shorter sentences? As it is, I really don't et what is what.

VNCCC (talk) 02:59, 24 November 2009 (UTC)

I agree that the passage in question was not as clear as it should be. I have made some modest changes. How does it read now? Boghog (talk) 07:43, 24 November 2009 (UTC)

No treatment?[edit]

Because no patent is available for tryptophan, it is not likely to be used commonly as a treatment for Dysthymia and SAD despite its apparent effectiveness. Why should it be like this? Do only patented medicines get reputation for treatmentability? --Abdull 09:28, 27 May 2006 (UTC)

No not at all. many currently unpatented medicines are used in treatments. this strikes me as claptrap, and it think it should be removed. i will take it on myself to do so in 3 days time. Xcomradex 01:49, 30 May 2006 (UTC)

That either didn't happen or got reverted, so I've done it. Gareth McCaughan 23:43, 30 August 2006 (UTC)

you can say its clap trap all you like, but its the truth. why has australia and america banned advertising or distribution of an Amino Acid, tryptophan (and 5htp), while most of europe and canada has had it available from pharmacies for 30 to 40 years?? did the fda ban trp in 1988 the year before the first SSRI was brought onto the market? its difficult to prove, of course. its also difficult to prove that america and australias medical system are totally owned and regulated by the New World Order (a big mac and fries). tryptophan is heat sensitive and we are being intentionally depleted as a population control measure. — Preceding unsigned comment added by (talk) 13:34, 12 May 2012 (UTC)


How can tryptophan be banned when it is a essential amino acids? wouldn't this be like banning water? --Abdull 09:37, 27 May 2006 (UTC)

It's not anything that contains tryptophan that is banned, just purified and concentrated tryptophan. Still, I agree, it's ridiculous. —Keenan Pepper 16:47, 27 May 2006 (UTC)

Notes on Tryptophan article[edit]

[[2]] Article with references to back it up. Putting it here temporarily so we can check to see what info is missing from the article and determine if the link or info from the link is suitable to post. What mostly prompted this post is a quote from the article:

"At the same hearing, Dr. Wurtman stated: Tryptophan in a bottle is not a nutritional supplement. In protein, it comes with 21 other amino acids, and you need all of them in order to utilize them and make protein. Pure tryptophan in pills or in a bottle is not natural. . . . The body cannot use it to make its own protein. There is not a single person in America who is tryptophan-deficient. Isolated amino acid deficiencies do not occur. People who have low blood tryptophan levels also have low blood levels of other essential amino acids as well, because these people are protein-deficient. Giving one amino acid to a protein-deficient person can make matters worse [9]."--geekyßroad. meow? 08:11, 14 July 2006 (UTC)
I noticed, believe it or not, that the statement has a really serious factual error in it. Proteins are fundamentally comprised of 20 amino acids, so the statement should have said that tryptophan comes with 19 other amino acids instead of 21.
WriterHound (talk) 06:37, 11 December 2007 (UTC)

Without decent references this article is worthless[edit]

I think it would be necessary to use medical publications as a source for this article.

It looks like an ADVERTISEMENT at the moment! It is to me as credible as the paper I use to wipe my 'you know what'.

I think the author might have a health food store where they sell tryptophan? Or why would they otherwise put up an article with no references? C'mon!

Why even bother if you dont bother googling up med pub sources and then digging those for results. Its never been easier, so I would say the author couldn't have been lazier.

Show some effort or remove it.

Agreed. This article is in desperate need of cleanup. I'm trying some, but I'm no expert in the field. Per Olofsson 21:40, 11 December 2006 (UTC)

No, no matter how badly an article is written or whether it lacks references completely, it does not make it worthless. One of the cornerstones of editing Wikipedia is that perfection is not required (see WP:EP). I ask anyone who finds a chapter or paragraph that is somehow wrong to improve it, rather than completely remove the work of others (see WP:BOLD). Find the references, move text and headings around, rewrite passages from a neutral point of view, find and add facts. What is lazy is destroying valuable content or whining about the lazyness of contributors.
Whether some fact has been verified is a different question than whether it can be verified at all. If it's a useful piece of information and has not been shown impossible to verify, please don't remove it. Wipe 02:29, 12 December 2006 (UTC)

Question about meat, and comments on above comments.[edit]

It reads "meat, fish, turkey, chicken" in part of the artical. Should that be "red meat"? I mean, fish, turkey, and chicken are all meat.

And the FDA is very corrupt. They tried to get rid of tryptophan for years, and as soon as they had an excuse, they did so, just before Prozac came out. Some FDA workers also work for the companies they are suppose to be regulating.

You just have to google FDA and "revolving doors" to see examples of this.

There is a lot of evidence about that, and on occassion a few convinctions, but rarely.

I'm going to go check out and update if necessary the wikipedia artical about the FDA now with some crediable referances.

Oh, and when it was illegal for humans, many people on health boards, myself included, just got it in the form of a powder designed for use by horses. user: Dream_Focus

Questionable text in two places Physiology section! (Marked below with [*** ***])[edit]


Tryptophan is biologically inactive as its L isomer. This may account for the episodes of eosinophilia-myalgia syndrome. L-tryptophan cannot cross the blood brain barrier.

5-HTP readily crosses the blood barrier, aiding in depression. [***("Aiding in" seems ambiguous. Perhaps "aiding in the treatment of" is what is intended here?)***] Marketed in Europe for this purpose under brand names like Cincofarm and Tript-OH [***for penis enlargement***].

Supplements do not require a prescription in America thanks to the Dietary Supplement Act.

Layman's Question...[edit]

Is it true that consuming tryptophan reduces nervousness? I've heard it recommended as a remedy before a nerve-wracking performance. --Grant M 06:58, 7 February 2007 (UTC)

Cheese Dreams[edit]

It is commonly said that eating cheese before going to bed causes nightmares. I had vivid dreams last night after a cheese sandwich - not nightmares but unusually vivid - and got to wondering whether there was anything in this or whether it was just coincidence. This article about a 2005 study by the British Cheese Board mentions tryptophan but this is a second hand report of a small study intended more for advertising than science so I'm still not convinced. Is tryptophan, in the amounts present in cheese, capable of affecting dreams in that way? If it is then I think "cheese dreams" should be mentioned in the article as a commonly known phenomenon. --Spondoolicks 13:32, 18 February 2007 (UTC) llok —Preceding unsigned comment added by (talk) 19:43, 29 May 2009 (UTC)

Turkey meat and drowsiness: Original research?[edit]

The sentence "Alcoholic beverage consumption at holiday feasts is likely to compound the effect [of drowsiness]" is marked as possible original research. That's just silly. It's common knowledge that alcohol causes drowsiness. I removed the original research? claim.

See Wikipedia:Common knowledge, in particular "Claims that something is a scientific fact" and "Medical claims." 04:34, 30 July 2007 (UTC)
The current argument in the section "Turkey meat and drowsiness" is nonsense. Serotonin does not make people feel drowsy, just generally happy, and the serotonin to melatonin conversion only occurs to a significant extent late at night, not during the afternoon or early evening. This section therefore is mainly erroneous speculation.Elroch (talk) 07:23, 29 August 2008 (UTC)
Thanks for your note. There is an extensive literature documenting serotonins involvement in the regulation of sleep, although the regulation is complex. See for example:
  • Ursin R (2002). "Serotonin and sleep". Sleep Med Rev. 6 (1): 55–69. doi:10.1053/smrv.2001.0174. PMID 12531142. Unknown parameter |month= ignored (help)
The connection between melatonin and sleep is much more clear cut. Therefore the Turkey meat and drowsiness section was not as clear as it should have been. I have therefore made the following change in the text: increases the production of sleep-promoting serotonin and melatonin in the brain to make clear that it is melatonin that directly causes the effect. Serotonin, since it is metabolized to melatonin, is an indirect cause of the effect. This mechanism is backed up by citations in the peer reviewed literature as already documented in the article. Cheers. Boghog2 (talk) 11:03, 29 August 2008 (UTC)

anti GM propaganda[edit]

I deleted this. it should not be replaced until someone can find a supporting reference in a scientific / medical journal. Just because some vanity press publishes something it doesn't make it true! — Preceding unsigned comment added by (talk) 15:23, 22 March 2012 (UTC)

In 1989, a large outbreak of a new, disabling, and in some cases deadly autoimmune illness called eosinophilia-myalgia syndrome (EMS) was traced to one source of L-tryptophan. The bacterial culture used to synthesize tryptophan by a major Japanese manufacturer, Showa Denko KK, had been genetically modified several times to increase tryptophan production during the 1980s.[1]-- 19:08, 28 July 2007 (UTC)

If you're going to delete that, you should also delete the following paragraph, which relies heavily on that one:

Along with the higher tryptophan concentrations in the modified culture media, the purification process had also been streamlined to reduce costs, and a purification step that used charcoal absorption to remove some impurities had been omitted.[2] The manufacturer maintained that this process modification allowed another bacterial metabolite through the purification, resulting in the presence of an end-product contaminant responsible for the toxic effects. As of 1996, Showa Denko had destroyed all modified organisms without FDA receipt of culture samples.[3][4] The FDA was unable to publicly establish with certainty what contaminant was the cause of the outbreak.

I take no position on the validity of the information in those two paragraphs, but I note that they seem to be talking about the same incident of a bad batch leading to an FDA ban, that is also described with references you might like better in the next few paragraphs of the article. 04:22, 30 July 2007 (UTC)

Well, do something, because currently the article still carries two references to "EMS" without explaining what it is, or even listing the full name. Consequently, the information in that section of the article seems to come out of nowhere. 20:05, 10 August 2007 (UTC)
I agree that the vanity press citation was biased and should be removed as well as some of the text which had a strong POV. I also agree that the EMS background needed to be re-insterted, however with more appropriate references. A quick search of PubMed yielded three citations in the refereed literature which linked tryptophan produced by Showa Denko to EMS as well as a more recent article with an alternative explanation. I have re-added a modified version along with these new references. Boghog2 21:40, 10 August 2007 (UTC)

The citations link to studies which do not support the assertion, but looking at the code there's a link to a book which has gotten press from HuffPo. The citations seem badly written, but I don't know the source enough to fix it. Fix the citation in the GMO reference? (talk) 02:37, 8 February 2012 (UTC)

What is being asserted is that tryptophan produced by Showa Denko to was responsible for the EMS outbreak and the citations definitely support this (see PMID 2355442 and PMID 8895184). However one of the links to a FDA statement is broken. A quick Google search unfortunately did not yield an suitable replacement. I am still searching. Boghog (talk) 05:02, 8 February 2012 (UTC) I found an archived version of the same web article and updated the link accordingly. Boghog (talk) 05:10, 8 February 2012 (UTC)
  1. ^ Smith, Jeffrey M (2003). "Chapter 4: Deadly Epidemic". Seeds of Deception: Exposing Industry and Government Lies About the Safety of the Genetically Engineered Foods You're Eating. Fairfield, Iowa 52556: Yes! Books. pp. pages 107-127. ISBN 978-0972966580. Unknown parameter |month= ignored (help)
  2. ^ Mayeno AN, Gleich GJ (1994). "Eosinophilia-myalgia syndrome and tryptophan production: a cautionary tale". Trends Biotechnol. 12 (9): 346–52. PMID 7765187.
  3. ^ James Maryanski. FDA. July 5, 1996.
  4. ^ Page S. Center for Food Safely and Applied Nutrition, FDA, Congressional Hearing, Subcommittee, July 18, 1991.

An advice column?[edit]

Articles on amino acids and various other biochemicals/nutritional supplements are vulnerable to becoming deluged with advice and "fringe biology" (IMHO) vs presenting broad encyclopedic overviews. For example, key biochemical processing of tryptophan is currently barely discussed whereas speculations on the effect of turkey meat on drowsiness finds space (not that I have anything against such theories). The tag {{howto}} might be applicable to this article. To quote: "1. Instruction manuals. While Wikipedia has descriptions of people, places, and things, Wikipedia articles should not include instructions, advice (legal, medical, or otherwise) or suggestions, or contain "how-to"s." --Smokefoot 16:10, 12 August 2007 (UTC)

Which Genetic Code?[edit]

"Tryptophan is an essential amino acid involved in human nutrition. It is one of the 20 amino acids encoded by the genetic code (as codon UGG)."

Which genetic code? Banana? Human, dog, etc? It's probably common to most animals, but I this sentence really needs to be qualified better!!! I would change it, but I'm not quite sure what to put.

WriterHound 17:19, 16 September 2007 (UTC)

The genetic code is unversal, so no qualification is indicated.--Smokefoot 17:32, 16 September 2007 (UTC)

Tryptophan Metabolism Image[edit]

There image showing tryptophan metabolism is slightly wrong. Serotonin is 5-hydroxytryptamine, not 5-hydroxytryptophan. Also the enzyme that catlyses the conversion of formylkynurenine to kynurenine is formamidase. Would change this myself, but I don't have a great deal of spare time these days! Alex 19:30, 4 November 2007 (UTC)

Thanks for pointing out the errors. You have sharp eyes and an impressive knowledge of tryptophan metabolism! I have replaced the figure with a new one correcting the errors noted above. Cheers. Boghog2 20:00, 4 November 2007 (UTC)

Not a problem. If it's any help my employment is in tryptophan metabolism research, so I'm forever seeing these metabolic pathways! I personally would create a section covering just tryptophan metabolism (this could in fact be an article of its own), as there are many other important metabolites, especially in the kynurenine pathway, that are not mentioned here. Either way the article has improved significantly since I last really read it 8 months ago!! Alex 23:06, 8 November 2007 (UTC)

Why Supplementation?[edit]

If it's so plentiful in normal foods like eggs and meat why does supplementation with L-Tryptophan help with all of these different conditions. I don't know enough about chemistry so if someone could help me understand this I would love it. —Preceding unsigned comment added by (talk) 04:42, 31 January 2008 (UTC)

Amino acids behave differently when they are ingested alone vs. when they are competing with other amino acids. Pocopocopocopoco (talk) 05:28, 31 January 2008 (UTC)

The Citations on this page need updated or removed[edit]

especially reguarding the triptophan content grid (14, 15) one is a PDF doc from an unverified source and the other doesn't even pertain to such a listing of various foods that contain triptophan. the PDF link (citation 15) is about chocolate additives in cigarette smoking, not triptophan. i can see why wikipedia articles get mocked in the media. —Preceding unsigned comment added by Baayne (talkcontribs) 22:11, 8 May 2008 (UTC)

Regarding the tryptophan content table, citation #14 is an exhaustive database of foods and the percentage by weight of nutrients that each food contains including the nutrient tryptophan. Hence this citation is a definitive, quantitative and, to the best of my knowledge, the most complete source of information regarding the percentage of tryptophan of various food stuffs. Most of the data in the dietary sources table came directly from this source, and if this citation were removed, the table would need to be deleted. Regarding citation # 15, while the main topic of this article as you correctly point out is cigarette smoking and not tryptophan, this article does contain background information about the levels of tryptophan in various foods. This second citation is a secondary source and contains a subset of the information contained in the first citation and therefore could be deleted. Cheers. Boghog2 (talk) 21:44, 7 June 2008 (UTC)
Table of tryptophan content in foods cannot be verified. It should be removed or replaced by another w/ data from reliable & verifiable sources.
That definitive, exhaustive nutrient database from which tryptophan content in foods had been obtained is no longer available through the link included in the reference section. If the reference is not revised I think the most sensible thing to do would be to delete the current list or try to replace it by another with reliable sources. By the way, the data of this table doesn't match by far most of the values given in the cigarette smoking article with had been also included as a complementary reference. Presumably, at least one of the two sources must be wrong.Heathmoor (talk) 18:02, 28 November 2009 (UTC)
The link was active as recently as a week ago (see Google cache). It appears that the server on which the database is hosted is temporarily down (perhaps it was overloaded by Thanksgiving related queries ;-). So I would ask you wait at least a few days before taking the drastic action of deleting the table because of a temporary outage of a database. Concerning your second point, it is not uncommon that measurements in different labs differ. There can be natural variations in the test substances, differences in extraction efficiencies, etc. This doesn't necessarily mean one or the other measurement is wrong. Again, I suggest that we wait until the USDA database is back up and we throughly recheck the numbers. Perhaps we can restrict the table to a subset of entries where the two sources closely agree. Cheers. Boghog (talk) 18:24, 28 November 2009 (UTC)
Update: USDA Nutrient Database is on-line again. Since there is a new version of the database, I have updated the link. Boghog (talk) 08:38, 29 November 2009 (UTC)

Turkey meat and drowsiness[edit]

I unfortunately don't have a source for this, but I believe it is accurate physiologically speaking... (if you can say that...) What _does_ happen when you eat a large meal of turkey (or any other large meal), is that your stomach fills up (of course) and this decreases the amount of space left in your abdominal and chest cavities for where the lungs normally expand into. Therefore you're actually decreasing the amount of air actually getting to your brain-- not to any amount critical of worry, but your body decides to save some energy, activate components of your parasympathetic nervous system, (rest and digest) and get drowsy. It's basic physiology, any B.Sc knows that... Someone should add it to the article, I'd be happy to if someone can ensure me it's not going to get instantly deleted for lack of sources. Let the health science graduates who know the science have a say. purpleidea (talk) 17:20, 5 June 2008 (UTC)

If what you say is true (referenced or not), I still can't see a reason for it it to be added to this article. As there is no reason for turkey meat specifically as opposed to any other meat, or indeed any other food, to cause this effect. If this is the mechanism by which eating large amounts of food causes drowsiness or fatigue, it'll probably be mentioned somewhere else on wikipedia, and a simple sentence with a link, rather than the long-winded explanation should suffice! Alex (talk) 20:39, 7 June 2008 (UTC)

Tryptophan and Bananas - an urban myth[edit]

Why banana is claimed to have plenty of tryptophan, when it actually has almost none? Sure the t/p-ratio is nice, but not only it has nothing to do with the actual t-content of bananas, there is also little or no explanation what this ratio actually does. -- (talk) 15:32, 6 August 2008 (UTC)

I agree with the above comment. My research on the web shows that the banana as a mood elevator via it's Tryptophan content is a huge urban myth.

A banana contains about 9mg Tryptophan per 100g edible portion whereas chicken has 240mg and lentils have 232mg [1] (talk) 17:13, 27 March 2015 (UTC)


  1. ^ [1]

Why the POV template?[edit]

This article has a POV template from October 2008, but there is no discussion on the talk page about potential POV since August. If these issues have been resolved the POV template should be removed. If there are other issues, please raise them here on the talk page and resolve them. Tamino (talk) 08:52, 18 October 2008 (UTC)

The justification for adding the {{pov}} template in this edit was "Tagged article as biased in anticipation of reverse edits" which in my opinion is not sufficient justification. This template should only be used for alert readers to biases which may exist in the current version of the article. If the bias has been removed, then the template should be removed. Furthermore the template should not be used in anticipation of possible future biases. Adding a template to warn users of bias when in fact none exists only serves to confuse readers. Therefore I have removed the template. Cheers. Boghog2 (talk) 09:12, 18 October 2008 (UTC)

tryptophan relation to seratonin levels and osteoporosis[edit]

There is a new study which claimed to indicate that tryptophan deprivation lowered seratonin levels and reduced bone loss. —Preceding unsigned comment added by (talk) 15:59, 27 November 2008 (UTC)


The many technical details about Fluorescence were removed from this article and sent to the article where fluorescence is treated in metrology, namely the article on Fluorescence spectroscopy#Tryptophan_Fluorescence. In other words, the information will be more appreciated there where fluorescence is the topic rather than the protein. I like to saw logs! (talk) 03:51, 4 January 2010 (UTC)

5-HTP Heart Risk[edit]

The section saying that 5-HTP creates a risk of heart valve disease should say that it may have a risk, as the citations relate to direct administration of serotonin. So although this is a fairly logical conclusion, it shouldn't be written as absolute truth. (talk) 05:41, 7 March 2010 (UTC)

An interesting view on 5-HTP and heart valve disease:- — Preceding unsigned comment added by (talk) 20:10, 9 July 2011 (UTC)

Wrong figure in Trp biosynthesis from chorismate[edit]

in the figure, the 3rd step involves n-(5'-phosphoribosyl)-anthranilate, the steps are alright but it's structure is inaccurate. The N of anthanilate should be directly bonded to the ribose ring, yet the figure shown has a kink, which indicates the presence of another C before connecting to the ribose ring, and is wrong.

I have also checked the Lehninge. plx replace the fig. — Preceding unsigned comment added by (talk) 10:25, 11 September 2011 (UTC)

Yes, there does appear to be an error in the image. I have asked the creator of the image to have a look and fix it. Thanks for catching the error and reporting it here. -- Ed (Edgar181) 11:47, 11 September 2011 (UTC)
Thanks for spotting the error. The figure has now been corrected. Boghog (talk) 12:17, 11 September 2011 (UTC)


It is an essential amino acid as demonstrated by its growth effects on rats.

this could use citation — Preceding unsigned comment added by (talk) 11:06, 22 October 2012 (UTC)

Lacose intolerance[edit]

Under the heading "Function," lactose intolerance is referred to as a disorder. This seems an odd way to describe the common conditions of all other mammals and most humans. Does the entire population of Thailand, for example, suffer from a "disorder" as a result of lacking one of the relevant mutations? It may rarely occur as a disorder, but it is otherwise the human norm. A failure to recognize its normality can cause problems in increasingly diverse urban societies. (talk) David Harley 11/23/12 —Preceding undated comment added 17:29, 23 November 2012 (UTC)

Minor Correction in diagram for synthezing of tryptophan[edit]

Hi, This might be a major undertaking to correct, but, for what it's worth, I would like to set the record straight in pointing out that in the diagram under the header "Biosynthesis and industrial production", the last molecule in the chain has a typo and should, of course, read: "tryptophan". Safetydude (talk) 23:44, 26 November 2012 (UTC)Safetydude.

I've asked RicHard-59 to fix it at commons:User_talk:RicHard-59#File:Tryptophan_biosynthesis_.28en.29.svg. --Rifleman 82 (talk) 01:05, 27 November 2012 (UTC)

Talk about Tryptophan into Niacin[edit]

The article should mention how tryptophan can be used to make vitamin B3 niacin. — Preceding unsigned comment added by (talk) 13:44, 31 March 2014 (UTC)

Article with cites about the Showa Denko impurities. GMO or no?[edit]

What is the question? Jytdog (talk) 22:05, 1 June 2014 (UTC)

Molecular Formula[edit]

What's the molecular formula?
Eg: Phenylalanine has a chemical formula of C9H11NO2 but a molecular forumla of C6H5CH2CHCOOH

~ender 2014-10-06 5:58:AM MST — Preceding unsigned comment added by (talkcontribs) 12:59, 6 October 2014 (UTC)

for the condensed formula see here Jytdog (talk) 13:07, 6 October 2014 (UTC)
That's certainly close to what I'm looking for. And, really nice information. But, I was looking to regularize the wikipedia articles, and... the condensed structural formula is not the molecular formula, and much harder to put into a purely text-based summary (that gets ripped to Google).
~ender 2014-10-06 6:18:AM MST — Preceding unsigned comment added by (talkcontribs) 13:18, 6 October 2014 (UTC)
if you cannot get to the exact thing you are looking from what i gave you, you should maybe reconsider doing what you are considering. Also, the chembox instructions tell us to give the molecular formula. making the kind of systematic change that you are thinking of making, is something you should discuss at the chembox template talk page before you do, or on the talk page of the guideline for using chemboxes. template is Template:Chembox; guideline is Wikipedia:Chemical infobox Jytdog (talk) 14:00, 6 October 2014 (UTC)
Examine the other amino acids if you have a problem with wikipedia's inconsistency. Merely trying to get the these articles into a similar state. Perhaps we should treat it like wikipedians do for other articles, and instead delete the information on the articles which do have that information :)
~ender 2014-10-06 12:34:PM MST — Preceding unsigned comment added by (talk)
i noticed that you deleted the unsigned template i added to your posting. please actually sign your posts using four tildas. the reasons for this are many and not signing your posts is considered disruptive behavior and will get you blocked, and if you persist, banned. what you are doing is not sufficient. please see Wikipedia:Signatures. Jytdog (talk) 14:05, 6 October 2014 (UTC)

Tryptophan and aging[edit]

I would like to point out that the scope of this article is wider than WP:MED, it also includes WP:MCB. As long as it is made clear that the studies are in animals, this should be fair game to include a section on tryptophan and aging. A good secondary source that discusses the evidence is here: PMID 23562344. Boghog (talk) 14:53, 29 December 2014 (UTC)

i really struggle with this boghog. at the end of the day, nobody cares whether mice live longer. the work in mice, and the reporting of it, only matter because people are trying to understand human health, and, i would guess, longevity freaks would read this and say "oh, i will for sure avoid tryptophan going forward" ugh. Jytdog (talk) 15:22, 29 December 2014 (UTC)
Some people are also interested in basic research. Of course, the reason why this research is funded is that it may eventually be applied to improve human health. The attitude that we should not include such information since it might be misinterpreted by some people amounts to censorship. Boghog (talk) 15:48, 29 December 2014 (UTC)
nope, censored is irrelevant to this. Please see WP:MEDRS and WP:MEDMOS. We don't provide the public with information about health based on animal studies. Jytdog (talk) 16:48, 29 December 2014 (UTC)
Wikipedia is the sum of all human knowledge. Animal studies are part of that knowledge. WP:MEDRS only applies to content that is within the scope of WP:MED and as I have stated above, the scope of this article is wider than WP:MED. Boghog (talk) 17:26, 29 December 2014 (UTC)
While we are quoting Wikipedia guidelines, I would suggest that you read the WP:MEDANIMAL section of WP:MEDRS which reads in part Where in vitro and animal-model data are cited on Wikipedia, it should be clear to the reader that the data are pre-clinical, and the article text should avoid stating or implying that the reported findings hold true in humans. So even MEDRS allows animal studies as long as it is carefully worded. Boghog (talk) 18:50, 29 December 2014 (UTC)
ok, so based on secondary sources, and no UNDUE weight, and properly couched. Jytdog (talk) 20:42, 29 December 2014 (UTC)

Wrong structure[edit]

The first structure on the right hand side is wrong with an extra carbon. The second structure is right. Why are there 2 pictures of tryptophan, with the second being called ball and stick model while it is clearly not? — Preceding unsigned comment added by Hieniemic (talkcontribs) 16:00, 23 December 2015 (UTC)

In psychiatry or in neurology?[edit]

The article reads:

Tryptophan affects brain serotonin synthesis when given orally in a purified form and is used to modify serotonin levels for research in psychology.[33]

Unfortunately I do not have access to the source text. It however appears unlikely to me that psychology was the intended word in this context. (talk) 05:46, 7 January 2016 (UTC)

I have simply removed "in psychology", the reference is about pharmacology, neurology, perhaps psychiatry. PaleoNeonate (talk) 11:29, 15 March 2017 (UTC)


The drug laws in Europe are very strict, particularly with the Indication "depression" or "insomnia", and L-tryptophan (or melatonin) is available as a prescription drug only. Its use as a dietary supplement in non-approved products is illegal, with a few exceptions in the Netherlands and the UK where non-registered supplements are much more tolerated. I am not necessarily an advocate of strict regulation but it is interesting to see how well-controlled the continental Europeans are approaching this. Osterluzei (talk) 06:57, 16 February 2016 (UTC)

Crystal structure of L-tryptophan[edit]

I was looking for the crystal structure of pure L-tryptophan to illustrate this article and found that it had only recently been determined: G. M. Day and co-workers, Acta Cryst. (2012). B68, 549-557. That paper notes that the crystal structures of the pure forms all the other standard L-amino acids apart from L-lysine have been determined.

Is there consensus yet on how to show the 3D structures of amino acid molecules? The issue is the zwitterionic forms are more realistic but confusing for some readers, whereas the neutral forms are simpler but do not exist in reality (perhaps with the exception of some strange gas-phase situation). We have a neutral structure, File:L-Tryptophan - L-Tryptophan.svg, in the Chembox at the moment, but that form is more of a concept than a real structure because one of the acid groups would protonate the amine forming a zwitterion.

Has this dilemma been settled elsewhere?

--Ben (talk) 11:09, 27 April 2016 (UTC)

Tryptophan in milk[edit]

The value "0,08" (if You calculate 2.34 % from 3.22 g, You get exactly 75 mg) is definitely wrong; searching the USDA database leads to 0,046g =(46 mg). --Cvf-ps (talk) 14:30, 4 December 2016 (UTC)

Data table inaccuracy[edit]

Using data from, ground beef has a tryptophan to protein ratio of approximately 0.5%, rather than the table's listing for beef of 1.12%. The entry for turkey does seem accurate though, at 1.11%. I couldn't find any specific data on tryptophan content from the cited USDA database. — Preceding unsigned comment added by (talk) 17:51, 14 December 2017 (UTC)

Inaccurate data table[edit]

Using data from, ground beef has a tryptophan to protein ratio of approximately 0.5%, rather than the table's listing for beef of 1.12%. The entry for turkey does seem accurate though, at 1.11%. I couldn't find any specific data on tryptophan content from the cited USDA database. Thus, turkey contains at least twice as much tryptophan per total protein than ground beef. (talk) 18:00, 14 December 2017 (UTC)

The problem is that the USDA site has completely been revised so one is no longer able to do the same type of searches that one previously could. I am certain that the numbers in the table were correct as of 2009-11-29 since I personally checked them. Unfortunately as of 14 December 2017, one can no longer do a similar check in the on-line USDA database. I have also checked the WayBack machine and one cannot reproduce the search results using that source. It appear that one can obtain the percentage of tryptophan in the total weight of beet and the total weight of protein in total weight of beet and from that calculate the percentage of tryptophan from beet protein. This type of calculation is allowed per WP:CALC. I don't have time to do this right now, but will look again this weekend. Boghog (talk) 21:30, 14 December 2017 (UTC)
In the current USDA Food Composition Database, one can list two nutrients (e.g., protein and tryptophan) at the same time and download the results in a csv file and import into a spread sheet for calculations. It turns out that the database contains many values for beef. For example somewhat different values are listed for different cuts of beef and for different preparation methods. Ditto for turkey. Listed below are the averages:
USDA Food Composition Database
Food Tryptophan/Protein (%) Standard Deviation Number of measurements
Hence according to the USDA Food Composition Database, the percentage tryptophan in beef or turkey protein is almost equal and the numbers are very similar to what is current listed in the article table. Digging further into the numbers, it appears that the percentage of tryptophan in ground beef is lower (~0.5%) than for some other cuts of beef. However the current table does not specify which type of beef, hence I think the numbers in current table are reasonably accurate. Boghog (talk) 06:39, 16 December 2017 (UTC)

Boghog (talk) 06:39, 16 December 2017 (UTC)