L Carnitine is Underrated. New Meta Review Reminds Us Why. The Fitness L arginine has two effects: it turns into nitric oxide and helps the body build protein. These effects give L arginine an array of potential benefits that range from heart health L Arginine & Proanthocyanidin granules belong to the class of nutritional supplements. Use of L Arginine and Praonthocyanidin granules: L arginine and proanthocyanidin granules are a nutritional supplement blend, often used to improve cardiovascular Full Fuel 365 L Arginine 1000 mg 21st Century Vitamins 21st Century Vitamins