Glutamine is a supplement that is used in weightlifting and bodybuilding, as well as by those who suffer for muscular cramps or pain—particularly elderly people. The main use of glutamine supplements is to replenish the body's stores of amino acids that have been used during exercise or even everyday activities. Glutamine can extremely improve recovery time after intense exercise PLUS its believed to help the body to metabolize protein.
Glutamine is HIGHLY recommended to be used after intense exercise and is also recommended during fasting or for people who suffer from physical trauma, immune deficiencies, or cancer. Ask any successful bodybuilder and they will tell you glutamine is an essential key for building muscle.
Bottom line, if you aren't taking glutamine you're leaving a lot of muscle on the table!