Quest L-glutamine supports gastrointestinal health & muscle function, thereby helping you to keep your digestive tract healthy & happy.L-Glutamine is an Amino Acid which the body incorporates into protein. It also has its own separate functions. Quest L-glutamine is the primary source of fuel for enterocytes (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, is stored in skeletal muscles as a fuel source & is required for normal immune function.