Dietary Supplement. Promotes Heart & Immune Health*. Promotes the Effects of Exercise*. Smart Facts: L-Arginine is one of 20 amino acids, the building blocks of protein and is popular with body builders and fitness enthusiasts.* L-Arginine can serve as an energy precursor and is one of the most important amino acids involved in heart and immune function.* No Artificial Color, Flavor or Sweetener, No Preservatives, No Sugar, No Milk, No Lactose, No Soy, No Gluten, No Wheat, No Yeast, No Fish, Sodium Free. *These statements have not been evaluated by the F.