Since 1996 Kyowa Quality Supports Healthy Nitric Oxide Levels in the Body Supports Cardiovascular Health Dietary Supplement Non GMO 3rd Party Tested Vegan Manufactured in a cGMP Facility This Product Meets The USP and FCC Monograph Requirements Healthy Origins® American-Made L-Citrulline supplies an amino acid that is a precursor to L-Arginine production in the body. Since L-Citrulline helps to boost L-Arginine levels, it is a great choice for athletes looking to optimize their athletic performance during high intensity workouts. L-Citrulline also serves as an important intermediate in the urea cycle. The urea cycle converts bodily ammonia into urea which is easily excreted by the body.