Arginine

About Arginine

Arginine is an amino acid that healthy adults can synthesize, mainly from citrulline in the kidneys, but it is considered conditionally essential because needs may exceed production during growth, severe illness, trauma or burns. It is the substrate from which nitric oxide synthase enzymes produce nitric oxide, a signaling molecule that relaxes blood vessels and plays roles in immunity and neurotransmission. The discovery of nitric oxide as a signaling molecule in the cardiovascular system was recognized with the 1998 Nobel Prize in Physiology or Medicine. Arginine is also an intermediate in the urea cycle, which disposes of excess nitrogen, and a precursor for creatine, polyamines and proline. Rich food sources include meat, poultry, fish, dairy, nuts, seeds and legumes. Arginine supplements are marketed for blood flow, exercise performance and erectile function, but because much oral arginine is broken down before reaching the circulation, results have been inconsistent and evidence remains mixed.