What is Arginine?

Arginine is one of the 20 amino acids that constitute protein. It exists as L-arginine and D-arginine form. However, the L-arginine is the more compatible form to human body. Since L-arginine can be synthesized in the body, it is called non-essential amino acid. The exception is that newborn infants are unable to produce L-arginine, therefore their only source for it is from their diet. L-arginine can be synthesized in the body from the amino acid citrulline.

Health Benefits of L-arginine

L-arginine is a precursor of nitric oxide and other metabolites, a component of collagen, enzymes and hormones (eg. vasopressin), ejaculate (seminal fluid and sperm), skin and connective tissues. L-arginine plays important roles in the synthesis of various protein molecules (eg. creatine and insulin). Other L-arginine benefits include regulation of platelet aggregation and lowering of blood pressure. It may also have antioxidant property.

L-arginine is converted to nitric oxide, which aids in the relaxation of blood vessels. Thus, an indirect benefit of L-arginine is improved blood circulation in the body, especially in the extremities (eg. genitalia). And as a result of that L-arginine helps in stimulating and maintaining penile erection. Research suggests that men with erectile dysfunction may benefit from intake of l-arginine rich foods or L-arginine supplement. L-arginine is a major component of ejaculate (seminal fluid and sperm). Therefore, it is important for maintaining healthy ejaculate volume.

Aditional L-arginine benefits include removal of excess ammonia and maintainance of nitrogen balance. It reduces accumualtion of compounds such as ammonia and plasma lactate, byproducts of physical exercise. It helps in liver detoxification, reduction of alcohol toxicity effects, and wound healing.

L-arginine Side Effects

A known side effect of L-arginine is that it undermines the effect of lysine in suppression of viral infection. Therefore, for a person infected with viruses (eg. herpes virus), it is recommended to reduce L-arginine supplement dosage or not to eat foods high in L-arginine. Pregnant and lactating women are advised to be cautious with their arginine intake and dosage. Other side effects of l-arginine (when taken in high dosage and for long term) are thickening and coarsening of skin.

According to some human studies , arginine-HCL consumed at high doses (> 9 g/d) has been associated with side effects such as nausea, gastrointestinal discomfort, and diarrhea.

Arginine deficiency

Deficiency of arginine could result delay in sexual maturity, impairment of the production of insulin, glucose tolerance, and liver lipid metabolism. However, it is uncommon to be deficient in arginine.

Food sources of L-arginine

L-arginine is found in high content in protein rich foods such as peanuts, walnuts, brazilnuts, cocunut, animal products (milk and milk products, pork, beef, chicken, turkey), seafoods, cereals (oats and wheat), and chocolate. Legumes such as soybean and chickpea are also rich natural sources of L-arginine.

A long list of foods with estimates of their arginine content: Arginine in foods.

L-arginine and other amino acids:
List of foods high in arginine content
L-arginine, nitric oxide and erection (erectile dysfunction)
Eating watermelon increases arginine level
Lysine health benefits and food sources

Herbs and sexuality:

Yohimbe: health benefits and side effects
Ginseng: health benefits and side effects
Ginkgo Biloba: health benefits and side effects

Erectile dysfunction related articles:
What is erectile dysfunction? How does erection occur?
What are the treatments for erectile dysfunction?


Long, J.H.D, Lira, V. A, Soltow, Q. A., Betters, J. L., Sellman, J. E. and Criswell, D. S. 2006. Arginine supplementation induces myoblast fusion via augmentation of nitric oxide production. Journal of Muscle Research and Cell Motility, Vol. 27(8), 577-584.

Clarkson, P., Adams, M.R., Powe, A.J., Donald, A.E., McCredie, R., and Robinson, J., et al., 1996. Oral L-arginine improves endothelium-dependent dilation in hypercholesterolemic young adults. J Clin Invest, Vol. 97, 1989–1994.

Chin-Dusting, J.P.F., Alexander, C.T., Arnold, P.J., Hodgson, W.C. , Lux A.S., and Jennings, EG.L.R.. 1996. ffects of in vivo and in vitro L-arginine supplementation on healthy human vessels. J Cardiovasc Pharmacol, Vol. 28, 158–166.