Theanine 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 mitigating glutamate toxicity. Jarrow Formulas Theanine is made enzymatically from amino acids and is identical to the theanine found in green tea.