L-Arginine is ext remely important for many body functions and is usually only naturally present in low quantities. L-Arginine is a precursor of nitric ox ide, 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. A single teaspoon provides 3,000 mg (3 g) of L-Arginine.