It is the most important amino acid supplement for athletes. L-Glutamine is considered a powerful anti-catabolic that helps protect muscles in daily activity and intensive training. Also it plays a critical role in immune system function. Glutamine is considered a "conditionally essential" amino acid. It is the preferred fuel source for rapidly dividing cells. Glutamine is the main muscle amino acid constituting about 2/3 of the free amino acid deposits in skeletal muscle. It is an anti-catabolic favors glycogen stores and ensures optimal recovery.