L-glutamine is an amino acid found in proteins of all life forms. It is classified as a semi-essential or conditionally essential amino acid. L-glutamine is the most abundant amino acid in the body, and plasma glutamine levels are the highest of any amino acid. L-glutamine is predominantly synthesized and stored in skeletal muscle. The amino acid L-glutamate is metabolized to L-glutamine in a reaction catalyzed by the enzyme glutamine synthase, a reaction which, in addition to L-glutamate, requires ammonia, ATP and magnesium. L-Glutamine is becoming one of the most widely-used supplements within the health supplement industry. Not only is it proving extremely popular with body builders, strength athletes and those interested in maximising physical strength and power, it is also becoming a hot product for the non-athletic individual interested in optimal health and strong immunity from illness.