L-arginine is a conditionally essential amino acid, which means that under normal circumstances, it can be manufactured by the body to meet its demands. In the case of poor diet or heavy physical stress, our biosynthetic pathway may not produce sufficient levels of arginine, and therefore part of it must be absorbed through food or supplements.

It is the only precursor of nitric oxide (NO) and an important precursor of creatine, and arginine supplements are generally popular among athletes and bodybuilders. Taking high-dose capsules is the easiest way to meet the increased needs of arginine.