L-Glutamine is the most abundant amino acid found in the body. It's made in the muscles and transferred by the blood into different organ systems. L-Glutamine is a building block for making proteins in the body. It's also needed to make other amino acids and glucose. L-Glutamine supplements might help gut function, immune function, and other processes, especially in times of stress when the body uses more glutamine.
People take glutamine for sickle cell disease, burns, to improve recovery after surgery, for injuries, and for complications of HIV/AIDS. It is also used for diarrhea, cystic fibrosis, obesity, lung cancer, and many other conditions, but there is no good scientific evidence to support most of these other uses.