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concern about structure[edit]

Isn't it supposed to have a fixed +1 charge in the amino acid side chain? there is resonance between the nitrogen atoms as well. — Preceding unsigned comment added by (talk) 02:05, 7 April 2013 (UTC)

i know the article indicates these things but the picture at the top should also point to this charge and resonance using dotted lines — Preceding unsigned comment added by (talk) 02:08, 7 April 2013 (UTC)

Corporate sponsorship of cited paper[edit]

Reference 15 "Antiviral effect of arginine against herpes simplex virus type 1" studies arginine effect on HSV-1. The study was funded by Ajinomoto Co. Inc. who just happens to sell arginine. The paper says the arginine used in the study was purchased from that same company. I was happy to have finally found a paper studying the effect of arginine on HSV until I read that. I also find it interesting that a number of places online (all selling lysine) say that lysine inhibits HSV and that arginine promotes the reproduction of HSV-1. But this paper says just the opposite: that arginine inhibits the reproduction of HSV-1. — Preceding unsigned comment added by (talk) 12:18, 9 October 2011 (UTC)

I concur. Also: the mentioned paper does not appear in the Herpes#Treatment section. (talk) 14:50, 11 March 2013 (UTC)

Treatment for sensitive teeth[edit]

How much truth is there to this? : —Preceding unsigned comment added by (talk) 20:03, 5 May 2010 (UTC)

It's well proven, Colgate was the original sponsor of the research as well. I believe there is a tidbit about calcium carbonate+arginine on another wikipedia page for sensitive teeth. Kasooi (talk) 22:22, 23 February 2012 (UTC)

Section now has as reference a meta-analysis (fancy review) that cites 18 clinical trials. Claim appears to be supported by research. David notMD (talk) 17:45, 12 June 2017 (UTC)


Can somebody please explain why is it so evidently that the need for this amino-acid is restricted to children ? Same for histidine. Thanks.

Healthy adults can synthesize arginine to meet needs, but children cannot, and so need to also be consuming arginine. The Wikipedia article Essential Amino Acid clarifies the distinctions among essential amino acids, conditionally essential amino acids and non-essential amino acids. David notMD (talk) 13:14, 12 June 2017 (UTC)

Vegetarian vs Vegetable sources and Chocolate?[edit]

It seems to me that milk and chocolate are vegetarian. Now if we are trying to say vegetable sources, then milk is definitely not one, but what about chocolate? Chocolate does not necessarily include milk. In fact, I have in my hands right now a Trader Joe's organic dark chocolate 73% super dark bar which does not include any animal product. I can find no actual measurements of chocolate's arginine or lysine content. So does anyone have a source to back up chocolate being on this page? Renduy 17:38, 15 November 2007 (UTC)

IUPAC Name[edit]

I have reverted back to the IUPAC name I added because I got the name from an IUPAC publication. I think these should be the correct names for all of the amino acids since they are from IUPAC. Borb 21:54, 10 August 2005 (UTC)

Not sure which name you are referring to, but "arginine" is not an IUPAC name. The IUPAC name is definitely listed under "other names." IUPAC names list each functional group and their position in the molecule, but "arginine" is a much simpler, commonly used name (which is why it is called a common name). —Preceding unsigned comment added by (talk) 16:41, 2 April 2010 (UTC)

Sexual uses[edit]

I had to delete that i just can't stand pseudoscience. Boris 13:48, 19 December 2005 (UTC)

fair enough but the article does state it may release prolactin. and that it is a precursor to NO. consider what viagra does wrt NO, and the role played by NO. also there has been newsreports of people who drank an energy drink (boost?) with ~1g arginine having a severe erection, and even resorting to surgery to aleviate the ahem, erection. 01:12, 18 June 2007 (UTC)

Other uses[edit]

Arginine is widely used in sports supplementation. Adding some information on this subject should be relevant. I have started to take l'arginine in hopes of increasing my sexual stamina and for ED. I will keep you posted of the results. i'm not convinced yet.

Hey,try taking some Citrulline in combination with the Arginine.The two aminos will work together great.

About the Prolactin issue,it should also state that SOME (some being the keyword here) bodybuilders stay away from free-form Arginine supplementation,on the other hand an entire supplement category exists around free-form Arginine.This category is called N.O supplementation.It usually consists of a pre-workout powder such as BSN N.O Xplode which was the product that started the entire trend of Nitric Oxide supplements.These powders usually contain some advanced form of Arginine (Arginine AKG),a few other aminos that work in syergy with Arginine such as Orthinine & Citrulline and some type of stimulant,usually Caffeine.

These supplements are very popular in the bodybuilding world due to the muscle volumizing effects they have when taken before a workout.Now regarding the Prolactin issue,I think many either don't know or just don't care as they use the supplements strictly for the cosmetic "pump" it gives them.

P.S I am very new to this Wikipedia thing,if I did not enter what I wrote in the right place I apologize.

My wifw ia prescriberd ARG9 by infertiity specialist. of course may be to realase procatone or genral supplement. I also started ARG9 ti enhance sexual stamina. but results r waited. if anybody has more knowledge plz tell. —Preceding unsigned comment added by (talk) 07:34, 5 January 2009 (UTC)

¶ There was a very recent newspaper report indicating a relation between arginine and Alzheimer's. Would someone please add some reliable info on this, please. Sussmanbern (talk) 00:45, 19 April 2015 (UTC)

Other sources[edit]

etc.? Could someone add some non-meat sources or a link to where one can find such information --Mig77 13:14, 17 March 2006 (UTC)

Why does it occur only in Canadian bacon - are pigs everywhere else arginine-free? —The preceding unsigned comment was added by (talk) 07:19, August 23, 2007 (UTC)

That term refers to the cut of meat, not its origin. —Preceding unsigned comment added by (talk) 19:34, 22 November 2009 (UTC)

Protonation state[edit]

The protonation state shown is impossible. Any conditions acidic enough to protonate the carboxyl would also protonate the amine and guanido... —The preceding unsigned comment was added by (talkcontribs) .

Excellent point, but the same problem affects the images of all the amino acids, not just arginine. I'll bring it up at Wikipedia talk:WikiProject Chemistry. —Keenan Pepper 22:27, 12 August 2006 (UTC)
Just to let you know, the chemical strucutre you have listed for this molecule is wrong and you are not showing the charges that are located on two of the nitrogens. The group double bonded to the last carbon should be NH2 with a + charge (you have only NH) and also the amino group (-NH3) on the alpha carbon (the carbon next the carboxyl group) should have a + charge on it. —Preceding unsigned comment added by (talk) 20:36, August 28, 2007 (UTC)

I believe it would be better to show arginine with the side chain charged. Truckhence 19:39, 2 November 2007 (UTC)

Argenine for energy and stomach[edit]

I'm taking L-arginine and it's a miracle supplement. I've sufferered from severe bloating and stomach pain for years and this helps that alot and gives me a lot of energy. Maybe it helps b/c it helps improve blood flow to my stomach and liver. It's worked miracles for me and I will keep taking it. —Preceding unsigned comment added by Interestedperson (talkcontribs) 17:42, 24 February 2008 (UTC)


The amino acid side chain of arginine consists of a 4-carbon aliphatic straight chain, the distal end of which is capped by a complex guanidinium group.

I'm not a chemist, but wouldn't that be a three-carbon chain? You don't count the α-carbon, right? Tualha (Talk) 15:44, 22 May 2009 (UTC)

Arginine in cosmetic formulations[edit]

Arginine is used in many cosmetic products to increase Vasodilation and give tissue an enlarged appearance for the duration of Vasodilation; Especially highly vascularized tisues like lips and genitalia. I know there are lotions with Arginine for the penile area eg. Maxoderm and Private Pulse. Does anyone know products formulated for lips? Alphaman7 (talk) 07:48, 7 October 2009 (UTC)

Claimed benefits of L-Argenine supplementation[edit]

I removed the following uncited claimed benefits of supplementation. L-Arginine is being aggressively marketed as a cure-all, but the science is not so strong. If you are aware of supporting evidence for any of these claims, please re-add them to the article, making appropriate citations to Reliable Sources. Thanks, Vectro (talk) 01:30, 11 December 2009 (UTC)

Review Articles[edit]

Wikipedia standards express a clear preference for the use of review articles as references, and there are many good reasons for this. The National Library of Medicine designates certain scientific journal articles in its database as review articles. The Wikipedia citation format used in this article does not contain a logical place for the word "review." I have identified the appropriate references in this article as review articles (as specified by NLM) by putting the word REVIEW after the page number -- since this is the only logical place to put this identifier that would not otherwise affect the format of the reference. X5dna (talk) 03:00, 16 January 2010 (UTC)

L-Arginine L-Pyroglutamate should not be merged into L-Arginine[edit]

This is a different subject and would just make the L-Arginine article bloated. —Preceding unsigned comment added by (talk) 21:27, 27 May 2010 (UTC)

Use for sex / condoms[edit]

There should be a section discussing whether Arginine actually increases bloodflow / potential safety of use in condoms. (see Danski14(talk) 20:52, 24 January 2011 (UTC)

L-arginine in atherosclerosis[edit]

L-Arginine is the substrate of eNOS, and the main precursor of NO in the vascular endothelium. Clinical studies suggest that l-arginine improves endothelial function in the presence of certain atherosclerosis risk factors such as hypercholesterolemia, smoking and possibly hypertension. However, despite the positive results derived from small case-control studies, which have demonstrated that in the presence of these particular risk factors l-arginine may improve endothelial function, it is still unclear whether chronic administration of l-arginine has the potential to prevent the development of coronary atherosclerosis in high risk subjects. Furthermore, in conditions such as diabetes mellitus, the effect of l-arginine on endothelial function is rather weak, possibly because of the greater extent of eNOS ‘uncoupling’ in diabetic vessels. Therefore, before l-arginine is supplemented at a clinical level, it is important to determine, in detail, those clinical conditions which are accompanied by l-arginine deficiency.

1: Siasos G, Tousoulis D, Vlachopoulos C, Antoniades C, Stefanadi E, Ioakeimidis N, Zisimos K, Siasou Z, Papavassiliou AG, Stefanadis C. The impact of oral L-arginine supplementation on acute smoking-induced endothelial injury and arterial performance. Am J Hypertens. 2009 Jun;22(6):586-92. Epub 2009 Mar 19. PMID 19300425.

2: Siasos G, Tousoulis D, Vlachopoulos C, Antoniades C, Stefanadi E, Ioakeimidis N, Andreou I, Zisimos K, Papavassiliou AG, Stefanadis C. Short-term treatment with L-arginine prevents the smoking-induced impairment of endothelial function and vascular elastic properties in young individuals. Int J Cardiol. 2008 Jun 6;126(3):394-9. Epub 2007 Jun 22. PMID 17588688.

3: Tousoulis D, Böger RH, Antoniades C, Siasos G, Stefanadi E, Stefanadis C. Mechanisms of disease: L-arginine in coronary atherosclerosis--a clinical perspective. Nat Clin Pract Cardiovasc Med. 2007 May;4(5):274-83. Review. PMID 17457351.

4: Siasos G, Tousoulis D, Antoniades C, Stefanadi E, Stefanadis C. L-Arginine, the substrate for NO synthesis: an alternative treatment for premature atherosclerosis? Int J Cardiol. 2007 Apr 4;116(3):300-8. Epub 2006 Jul 24. Review. PMID 16860889. — Preceding unsigned comment added by (talk) 10:12, 25 May 2011 (UTC)

L-arginine solubility mention, please?[edit]

The solubility of L-arginine? Nice official data and diagrams. How about at least a mention of solubility characteristics? Typically g/dl and at several temperatures in water, ethanol, and sometimes a liquid in which the compound is unusually soluble. Or at at least a mention like: "Highly (moderately, etc) soluble in water.
Mykstor (talk) 23:05, 8 November 2011 (UTC)

L-arginine supplements[edit]

The first section of this page concludes with the line: "In general, most people do not need to take arginine supplements because the body usually produces enough.[4]" I am not sure if I follow this logic here, as, in general, most people do not need to supplement their intake of any amino acid. Should this say that most people do not need to obtain arginine from their diet because the body produces enough? I think using the word "supplements" has pharmaceutical connotations. The reference used is also problematic as it does not seem to apply specifically to this sentence. Vokesk (talk) 17:03, 13 January 2012 (UTC)

arginine biosynthesis circular reference[edit]

Arginine is made in the urea cycle from citrulline, which can be derived from arginine via NO synthesis. That is a nice contribution into the topic of metabolic pathways, but doesn't explain the origin of carbon skeleton at all. — Preceding unsigned comment added by (talk) 12:04, 14 March 2012 (UTC)


The pKa should be changed from 2.48 to 12.48 (and the pKb should be changed accordingly). Thanks. — Preceding unsigned comment added by (talk) 19:25, 2 September 2012 (UTC)


   -- Pain
       mmh, i think that is the pka of the whole molecule, but it would be useful to have the pka of side chain too.  — Preceding unsigned comment added by Pain-proof (talkcontribs) 17:05, 3 February 2015 (UTC) 


Apparently it's in shampoo - I just saw J-lo on tv and she said so.

Struggling to reconcile this with reality, but just thought I'd raise it :

Raised something else in me, perhaps this is related to the erectile dysfunction use case?

Sgt101 (talk) 20:36, 5 March 2013 (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 5:57:AM MST — Preceding unsigned comment added by (talkcontribs) 12:57, 6 October 2014 (UTC)

for the condensed formula see here Jytdog (talk) 13:16, 6 October 2014 (UTC)
OP posted this on several amino acid pages; please see discussion here: Talk:Tryptophan#Molecular_Formula

Arginine Supplements[edit]

"Most healthy people do not need to supplement with arginine because their body produces sufficient amounts." Source linked to does not directly support this assertion. — Preceding unsigned comment added by JosephV (talkcontribs) 02:13, 16 November 2015 (UTC)

Picture needs to be corrected[edit]

The second picture has a NH2 that appears to be bound by its H, when in fact it is bound by the N of NH2. Myoglobin (talk) 00:21, 11 May 2016 (UTC)

Shifting enantiomers[edit]

This article begins by treating α-arginine, then halfway along we start seeing L-arginine mentioned without any mention of how the enantiomers differ, if at all. :Kortoso (talk) 16:34, 11 July 2017 (UTC)

Synthesis in humans from glutamine appears possibly to be incorrect[edit]

Re. this statement at the end of paragraph 2:

"...and can be synthesized in the body from glutamine via citrulline."

The referenced article indicates that arginine is synthesized from ornithine (as does discussion on the Ornithine page). It also indicates that ornithine is synthesized from glutamine in the gut [emphasis mine]. Other references indicate that this transformation is accomplished by bacteria (E. coli) in the gut, and that the enzymatic pathway in question does not exist in humans. See this page on ornithine biosynthesis and PDB entries referenced therein.

Eris8x6 (talk) 18:59, 6 March 2018 (UTC)