Double Strength Amino Acid Conditionally Essential Amino Acid Nitric Oxide Precursor Non-GMO A Dietary Supplement Kosher Amino Acids Family Owned Since 1968 GMP Quality Assured L-Arginine is conditionally essential basic amino acid involved primarily in urea metabolism and excretion, as well as in DNA synthesis and protein production. It is an important precursor of Nitric Oxide (NO) and thus plays a role in the dilation of blood vessels. The L-Arginine used in this product is Pharmaceutical Grade.