L-arginine is an important amino acid that your body uses to make proteins. One of the more important functions of L-arginine is its role in Nitric Oxide (NO) production. NO is a potent vasodilator, meaning it is able to relax muscles around blood vessels and widen them. Wider, more relaxed, blood vessels lead to more vigorous flow of blood, which helps reduce blood pressure. This also helps provide sufficient blood to exercising muscles, thereby enhancing athletic performance. Sufficient supply of blood and nutrients to exercising muscles also leads to greater endurance and reduced muscle soreness and fatigue. Supplementation of L-arginine is also associated with increased muscle mass. L-arginine stimulates the release of growth hormones and also promotes fat metabolism. Apart from its obvious role in protein synthesis, L-arginine also helps remove waste products from the body, in the form of ammonia and stimulates the release of insulin, that helps in maintaining healthy blood sugar levels in the body.