NUTRIWORKS L-Ornithine 200gL ORNITHINE Instant powder containing the pure form of the amino acid L Ornithine L Ornithine is a special so called catalytic amino acid with a unique ergogenic effect. As part of the supplementation, it is used separately, or in synergistic combination with Arginine or L Citrulline. The main function of Ornithine in the body is to support the physical function of muscle mass, especially through the breakdown of excess ammonia, which arises due to