Healthy Origins American-Made L-Arginine supplies an amino acid produced by the body to serve as a building block for proteins. L-Arginine is renowned for its primary function as a precursor to Nitric Oxide (NO) production in the body, but recent studies have shown that L-Arginine may also play a beneficial role in immune support and maintaining healthy blood sugar. Consider taking Healthy Origins L-Arginine with Healthy Origins L-Citrulline for enhanced athletic support.*