Nature’s Velvet L-Citrulline DL Malate Powder is an amino acid and a precursor to Arginine. Citrulline is one of the most popular inclusions in pre-workout drinks. Citrulline malate powder includes a compound called malic acid, which is found in many fruits and vegetables and may increase energy. This supplement includes a 2:1 ratio of citrulline and malate. Citrulline also plays an important role in the maintenance of a healthy immune system.