Arginine 

Arginine, also called l-arginine, belongs to the basic amino acids. The system converts arginine into nitric oxide important for its balance, as well as agmatine and glutamic acid. The role of arginine in the body is broad: it widens and makes the blood vessels more elastic, improves immunity, regulates insulin secretion, promotes mass building, affects the production of collagen and the elimination of ammonia from the body.