L-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. Our NOW natural and organic Supplements are an effective way to ensure you and your loved ones are getting essential vitamins, minerals and nutrients for daily optimal health. Since 2000, the NOW brand has been supporting Canadians with a mission to provide products that empower people to lead healthier lives. 70% of the NOW products in Canada are made or packaged in Guelph, Ontario, employing hundreds of Canadians from coast to coast. NOW performs 31,000 quality tests every month to ensure you get the highest quality supplements at the best price possible. Our promise - what is on the label, is precisely what is in the bottle.