Arginine is an amino acid that has many functions in the body.* It is metabolized to nitric oxide, which is a necessary factor in the normal dilation of blood vessels, to help support normal blood flow and heart health.* L-Arginine also maintains epithelial integrity of the gastrointestinal tract and skin, while enhancing collagen synthesis.* L-Arginine is one of the two main amino acids which promote sperm motility.