Free Form. Supports Circulatory Health. Nitric Oxide Stimulator. Gluten Wheat & Dairy Free. Suitable for Vegetarians. L-Arginine is an amino acid that promotes heart health. It stimulates nitric oxide a compound involved in circulatory and immune function. Nitric oxide degrades very rapidly after its formation. L-Arginine serves as the precursor for continued nitric oxide production. This product provides Free Form L-Arginine to promote optimal absorption and assimilation.