NOW® L-Arginine comes in extra strength 1,000 mg tablets and is non-GMO. Arginine is a 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. Natural color variation may occur in this product.   DOUBLE STRENGTH L-ARGININE: NOW offers this non-GMO, double strength L-Arginine supplement in 1,000 mg tablets. NITRIC OXIDE PRECURSOR*: Arginine plays an important role in the dilation of blood vessels.* CLASSIFICATIONS/CERTIFICATIONS: Non-GMO, Kosher, Soy Free GMP Quality Assured: NPA A-rated GMP certification means that every aspect of the NOW manufacturing process has been examined, including our laboratory/testing methods (for stability, potency, and product formulation). Dairy Free;Egg Free;Halal;Kosher;Made w/o Gluten;non-GMO;Nut Free;Soy Free;Vegan / Vegetarian