Amino Acids Keto Friendly Protein Metabolism 1:1 Ratio Informed-Sport.Com - Trusted by Sport Informed Choice.Org - Trusted by Sport A Dietary Supplement Steroid Free Non-GMO GMP Quality Assured The amino acids arginine and citrulline play an integral role in the body's metabolism and utilization of protein and are essential for the maintenance of muscle tissue. Arginine is a precursor to nitric oxide (NO), which promotes increased circulation by relaxing blood vessels. Citrulline is necessary for the elimination of ammonia, a toxic by-product of exertion, thereby supporting the body's natural recovery processes after exercise. In addition, excess citrulline is converted to arginine, helping to sustain arginine and NO levels better than arginine alone.