L-Arginina

The nitric oxide molecule is made from the amino acid L-Arginine. It is usually found in certain ergogenic products containing Nitric Oxide (NO) as it potentiates the vasodilatory effects. Increasing the intake of this precursor can raise nitric oxide levels when exercising.
L-Arginine is one of the 20 amino acids that are part of proteins. In hepatic tissue, arginine can be synthesized in the ornithine (or urea cycle) cycle. This amino acid is involved in many of the activities of the endocrine glands.
L-Arginine is an essential amino acid and can stimulate immune function by increasing the number of leukocytes. L-Arginine is involved in the synthesis of creatine, polyamines and DNA. It can lower cholesterol to improve the capacity of the circulatory system, as well as stimulate the release of growth hormone (somatropin), reduce body fat levels and facilitate recovery of athletes due to the effects of removing ammonia (muscle wastes resulting from anaerobic exercise) of the muscles and convert it into urea that is excreted in the urine.