Quest L-Arginine contains nitric oxide which is produced from arginine; nitric oxide is vasodilatory, it has a major regulatory role in blood flow, blood pressure and erection of the penis. Use to support cardiovascular health and male sexual function. Free form.Quest L-Arginine releases amino acid used to synthesise protein. L-arginine is involved in the production of urine and is used in the synthesis of creatine, used to provide immediate energy to intensely working muscles.Directions:Take one to four capsules daily on an empty stomach. Swallow with water. Do not exceed directions for use.Actives:L-Arginine 500 mgIngredients:L-Arginine, Capsule Shell (Hydroxypropylmethylcellulose,Water), Magnesium StearateWarnings:Do not exceed directions for use.