Quest L-Glutamine is used to support gastro-intestinal health and muscle function. L-glutamine is the primary source of fuel for enterocytes - the cells lining the inside of the small intestine. It is involved in brain function through the glutamine-glutamic acid cycle. L-glutamine detoxifies ammonia in the brain, and is stored in skeletal muscles as a fuel source. L-glutamine is required for normal immune function. It is in a free-form, simple for the body to assimilate - and is suitable for vegetarians and vegans.