L-arginine is converted in the body into a chemical called nitric oxide. Nitric oxide causes blood vessels to open wider for improved blood flow. L-arginine also stimulates the release of growth hormone, insulin, and other substances in the body.Increased strength through the increase in muscle mass is not the only benefit or L-arginine for bodybuilding. ... When nitric oxide is released, it expands the blood vessels by relaxing the muscles of their walls. The result is lowered blood pressure and increases blood flow to the muscles during your workout.