Theanine 100 is a unique amino acid found almost exclusively in green tea that exerts beneficial effects on brain metabolism. Theanine induces relaxation without causing drowsiness, as measured by increased generation of alpha-waves. Theanine may improve learning ability and sensations of pleasure by affecting dopamine and serotonin neurotransmitters in the brain. Also, Theanine exerts protective effects on the brain by antagonizing glutamate toxicity.Jarrow Formulas Theanine 100 is 100% L-theanine, made enzymatically from amino acids and is identical to the theanine found in green tea.