L-Arginine Free-Form Promotes Increased Circulation L-Arginine is a crystalline, free-form amino acid. It is an important factor in muscle metabolism and works to transport, store, and excrete nitrogen. It is a precursor for nitric oxide, which promotes increased circulation by relaxing blood vessels.* 500 mg Capsule Option Available: 50, 100 Suggested Use: 2 capsules, 1 to 3 times daily between meals. Allergies: Contains no yeast, dairy, egg, gluten, corn, soy or wheat. Contains no sugar, starch, salt, preservatives, or artificial color, flavor or fragrance.