Arginine is one of the most important amino acids present in the human body.
Arginine is one of the 20 amino acids that make up proteins in the human body.

Arginine is industrially produced as a white crystalline powder by fermentation of carbohydrates and is odorless but has a bitter taste.
It is readily water soluble but hardly soluble in alcohol.

In the pharmaceutical field, arginine is administered orally or by infusion to patients with liver disease caused by impaired urea cycle.

Arginine has many benefits.
It is well known that arginine intake promotes vasodilatation 1), improved blood flow 1,2), and growth hormone secretion 3).
Arginine enhances cytotoxicity and immunizes natural killer cells (NK cells; antibody-independent lymphocytes) and lymphokine-activated killer cells (LAK cells; lymphocytes with active cytotoxicity induced by lymphokines). Promotes reaction 4).

Arginine is known to stimulate insulin secretion and is used as a non-glucose secretagogue (a drug that causes or stimulates secretion) to measure insulin secretion levels5).
Arginine is involved in the detoxification of ammonia as a component of the urea (ornithine) circuit in the liver6), and exhibits a detoxification promoting effect7).
Arginine is converted to ornithine and a polyamine precursor by the action of arginase 8,9). Polyamines have been shown to be involved in tissue growth9).
Arginine is known to be absorbed by oral ingestion10), and oral intake of polyarginine has been shown to be effective in animals and humans3,11,12).
There are few records showing side effects regarding the upper limit of arginine intake in human food (6th ICAAS Workshop on Evaluation of Dietary Amino Acid Intake) 13).
According to clinical trials that verified the effects of arginine muscle strengthening and blood flow improvement in adult subjects, the daily intake required for improvement is 1-8 g. 1,2,14). No undesirable side effects have been reported due to arginine intake.
In the recently proposed OSL (Observed Safe level), the OSL of arginine is 20 g / day15).
In an acute oral toxicity study of arginine in rats, the half-lethal dose (LD50) is 16 g / kg (body weight) 16).

References
1.Hambrecht R. Hilbrich L. Erbs S. Gielen S. Fiehn E. Schoene N. Schuler G. Correction of endothelial dysfunction in chronic heart failure: additional effects of exercise training and oral L-arginine supplementation.Journal of the American College of Cardiology.35(3):706-13, 2000
2.Wolf A. Zalpour C. Theilmeier G. Wang BY.Ma A. Anderson B. Tsao PS.Cooke JP.Dietary L-arginine supplementation normalizes platelet aggregation in hypercholesterolemic humans.Journal of the American College of Cardiology.29(3):479-85, 1997
3.Besset A. Bonardet A. Rondouin G. Descomps B. Passouant P. Increase in sleep related GH and Prl secretion after chronic arginine aspartate administration in man.Acta Endocrinologica.99(1):18-23, 1982
4.Brittenden J. Park KG.Heys SD.Ross C. Ashby J. Ah-See A. Eremin O. L-Arginine stimulates host defenses in patients with breast cancer.Surgery.115(2):205-12, 1994
5.Eremin O. ed. L-Arginine:Biological aspects and clinical application.Chapman & Hall.15-8, 1997
6.Rodwell VW.Chapter 31:Catabolism of Proteins and of Amino Acid Nitrogen. in Harper’s Biochemistry 25th Edition.Murray RK.Mayes PA.Rodwell VW.Granner DK eds.McGraw-Hill/Appleton & Lange.NY.USA.313-22, 1999
7.Bessman SP.Shear S. Fitzgerald J. Effect of arginine and glutamate on the removal of ammonia from the blood in normal and cirrhotic patients.New England Journal of Medicine.256(20):941-3, 1957
8.Rodwell VW.Chapter 32:Catabolism of the Carbon Skeletons of Amino Acids. in Harper’s Biochemistry 25th Edition.Murray RK.Mayes PA.Rodwell VW.Granner DK eds.McGraw-Hill/Appleton & Lange.NY.USA.323-46, 1999
9.Rodwell VW.Chapter 33:Conversion of amino acids to specialized products. in Harper’s Biochemistry 25th Edition.Murray RK.Mayes PA.Rodwell VW.Granner DK eds.McGraw-Hill/Appleton & Lange.NY.USA.347-58, 1999
10.Tangphao O. Grossmann M. Chalon S. Hoffman BB.Blaschke TF.Pharmacokinetics of intravenous and oral L-arginine in normal volunteers.British Journal of Clinical Pharmacology.47(3):261-6, 1999
11.Elam RP.Morphological changes in adult males from resistance exercise and amino acid supplementation.Journal of Sports Medicine & Physical Fitness.28(1):35-9, 1988
12.Barbul A. Rettura G. Levenson SM.Seifter E. Wound healing and thymotropic effects of arginine: a pituitary mechanism of action.American Journal of Clinical Nutrition.37(5):786-94, 1983
13.The 6th Workshop on the Assessment of Adequate Intake of Dietary Amino Acids.The Journal of Nutrition.137, Supplement, 2007.
14.Elam RP.Hardin DH.Sutton RA.Hagen L. Effects of arginine and ornithine on strength, lean body mass and urinary hydroxyproline in adult males.Journal of Sports Medicine & Physical Fitness.29(1):52-6, 1989
15.Shao A. Hathcock JN.Risk assessment for the amino acids taurine, L-glutamine and L-arginine.Regulatory Toxicollogy & Pharmacology.50(3):376-99, 2008
16.Amino Acid Data Book.Japanese Society for Amino Acid Sciences.2010

・Is there anything L-arginine cannot do?
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