Now Double Strength L- Arginine 1000 mg Tablets provides 1g L-Arginine to promote optimal absorption and assimilation. L-Arginine is a conditionally essential basic amino acid involved primarily in urea metabolism and excretion, as well as DNA synthesis. It is an important precursor of Nitric Oxide (NO) and thus plays a role in the dilation of blood vessels. Arginine supports the effect of exercise and is involved in various important pathways throughout the body. L-Arginine may enhance exercise performance by increasing nitric oxide in the body, which improves blood flow and oxygenation to muscles. It brings relaxation of the cells that make up blood vessels, as well as blood pressure regulation. This product has twice the L-Arginine (1,000 mg per tablet) as in the brand's regular strength product (500 mg per capsule).