Arginine WHAT IS ARGININE? Ever wonder what better blood flow could do for your heart health and exercise performance? Though not as well known as many others, Arginine (or L-Arginine) is an anabolic amino acid that is intimately involved in building protein to help build muscle and repair tissues. A conditionally essential amino acid, arginine is a precursor for the synthesis of urea, nitric oxide, polyamines, proline, glutamate, creatine, and agmatine. Once inside your body, arginine is converted into nitric oxide, which causes blood vessels to widen. https://www.nationalnutrition.ca/amino-acids/single-aminos/arginine.html #Arginine