l-Arginine

*Versatile nitric oxide precursor

Arginine supports nitric oxide formation, important for healthy  dilation of blood vessels, circulation, and blood flow. In a  prospective, double blind trial, l-arginine supplementation supported  healthy endothelial function in blood vessels of male volunteers.  In other studies, l-arginine promoted healthy platelet function  and enhanced exercise tolerance. In men with low urinary nitric  oxide values, l-arginine may support healthy sexual function.  Some but not all research involving l-arginine supplementation  for sperm motility has produced positive results. Arginine plays  a role in the synthesis of hormones such as insulin and growth  hormone, and has demonstrated the potential to support glucose  metabolism and growth hormone production respectively. Because  of its effect on nitric oxide production, l-arginine is theoretically  best avoided by individuals with migraines, depression, autoimmune  disorders, and kidney or liver disease.