Although our body has the ability to make L-Arginine, it may be important for many of us to also take a supplement. L-Arginine is extremely important for many body functions and is usually only naturally present in low quantities. L-Arginine is a precursor of nitric oxide, which is necessary for the healthy dilation of blood vessels, circulation, and blood flow. Because of this, L-Arginine also supports a healthy immune system and athletic performance. Each capsule contains 675 mg of L-Arginine.