NOW Pro-GH is an amino acid supplement that has been designed to support optimal sports performance. Pro-GH contains Arginine, Ornithine, and Glutamine which are necessary for maintenance of nitrogen balance and help to rid the body of excess ammonia. Lysine, an essential amino acid, is an essential component of proteins and muscle tissue and is needed for the body's production of hormones, enzymes, and collagen. Glycine, known for its role in glycogen synthesis, helps to support muscular energy output. Finally Glutamine and Glycine help to support healthy immune responses, especially during times of physical stress and intense exercise.