Glutamine is the most common amino acid found in your muscles - over 61% of skeletal muscle is Glutamine. Glutamine consists of 19% nitrogen, making it the primary transporter of nitrogen into your muscle cells. During intense training, Glutamine levels are greatly depleted in your body, which decreases strength, stamina and recovery. It could take up to 6 days for Glutamine levels to return to normal - and Glutamine plays a key role in protein synthesis. Studies have shown that L-Glutamine supplementation can minimise the breakdown of muscle and improve protein metabolism. Glutamine (like other alpha-amino acids) is involved in regulating protein synthesis and breakdown. However, there's far more to it than that. Glutamine significantly affects BCAA metabolism, gut barrier maintenance, normal immune function, glucose formation, water transport, neurotransmission, and more. Researchers are suggesting that Glutamine is the most important amino acid to the bodybuilder. It provides a component in muscle metabolism and cellular support not shared by any other single amino acid, making the benefits of L-Glutamine supplementation a realistic venture.