Glutamine [gloo-tuh-meen], a non-essential amino acid, is one of the most abundant amino acids found in muscles. It plays an important role in muscle function during and after exercise. Each serving of GNC L-Glutamine powder supplies 5,000mg of L-Glutamine and blends easily with and beverage or sports drinks. It serves as fuel for the immune system and maintenance of proper intestinal function. Pro Performance L-Glutamin is tested and certified Banned Substance Free. GNC L-Glutamine powder is gluten and lactose-free.