Fortify your muscles and your mind every day with the pure amino acid nutrition of L- Glutamine! A popular favorite among fitness buffs, glutamine is the most abundant amino acid in skeletal muscle tissues, where it works to promote strength and endurance—but that's not all it does. Glutamine's unique molecular structure allows it to pass through the blood/ brain barrier to nourish vital brain tissues. Once in the brain, glutamine is converted into glutamic acid, the base material for key neurotransmitters needed for healthy mental and nervous system function.