Increase Muscle Pumps. Increase Vascularity. Increase Muscle Hardness. A2 Pump is an essential form of arginine (C15H22N4O2HCl) designed to penetrate the lipid membranes of muscle cells where its unique molecular structure increases nitric oxide production resulting in full hard pumped muscles. A2 Pump works at only a fraction of the dosage required with other forms of arginine. The effects of A2 Pump are noticeable within just a few days of use.