Arginine

Arginine or L-arginine is a complex, nitrogen-rich amino acid that is available as a nutritional supplement.

Purpose
Arginine is one of the 22 amino acids used by human cells to make proteins. Arginine also plays a role in many critical metabolic pathways. It is a precursor for nitric oxide (NO) when catalyzed by nitric oxide synthase (NOS) enzyme. It is also a precursor to other amino acids and amino-acid derivitives including proline, citrulline, ornithine, creatine, and agmatine. It also plays an essential role in the urea cycle, which removes nitrogen-containing waste from the body. Thus, arginine has a role in many different bodily systems including protein metabolism, vasodilation, modulating the immune system, neurotransmission, ammonia detoxification, cell signaling and muscles.

Evidence
Arginine may help reduce fatigue, and may help prevent or treat heart or circulatory diseases.

Costs and availability
Available over the counter.

Risks and safety
In a review summarizing current data on safety, pharmacokinetics, and effectiveness of oral arginine in adults, the authors concluded that, "Collectively, the data suggest that Arg supplementation is a safe and generally well-tolerated nutriceutical that may improve metabolic profiles in humans", (dosages and exceptions noted in report).

Learn more

 * Arginine - PubChem
 * Arginine metabolism - Journal of Nutrition