Jarrow Formulas Arginine + Ornithine contains only crystalline, pure free form amino acids. L-Arginine is a semi-essential amino acid synthesized by the body from Ornithine. Arginine and Ornithine support protein synthesis as they are involved in the transport and storage of nitrogen. Arginine, as a part of physical performance, is used by muscle tissue to produce creatine.* Each capsule contains 250 mg of Ornithine from 319 mg of Ornithine HCl (Hydrochloride), and 500 mg Arginine from 602 mg L-Arginine HCL.