L-arginine is an amino acid that helps the body build protein. It also releases nitric oxide into the blood. Nitric oxide acts to widen blood vessels in the bloodstream, which may help certain circulatory conditions. Forever Argi + is a supplement based on L-arginine, ribose, vitamins and plants with sugars and sweeteners, for effective support during and after exercise. Vitamins C, B6 and B9 contribute to a normal yield of energy metabolism and glycogen.