"Glutamine is the most abundant amino acid (building block of protein) in the body. The body can make enough glutamine for its regular needs, but extreme stress (the kind you would experience after very heavy exercise or an injury), your body may need more glutamine than it can make. Most glutamine is stored in muscles followed by the lungs, where much of the glutamine is made.

Glutamine is important for removing excess ammonia (a common waste product in the body). It also helps your immune system function and appears to be needed for normal brain function and digestion.

You can usually get enough glutamine without taking a supplement, because your body makes it and you get some in your diet. Certain medical conditions, including injuries, surgery, infections, and prolonged stress, can lower glutamine levels, however. In these cases, taking a glutamine supplement may be helpful."Source UMM