Theanine (The)

Theanine is an amino acid and a glutamic acid analog primarily found in tea (Camellia sinensis), and also in the basidiomycete mushroom Boletus badius and in guayusa. The L-enantiomer is the form which is found in tea and used as a supplement by humans. Able to cross the blood–brain barrier, theanine has psychoactive properties. Theanine has been studied for its potential ability to reduce mental and physical stress, improve cognition, and boost mood and cognitive performance in a synergistic manner with caffeine. Theanine promotes alpha wave production in the brain. While structurally similar to the excitatory neurotransmitter glutamate, theanine has only weak affinity for the glutamate receptor on postsynaptic cells. It also has low affinity for AMPA, kainate, and NMDA receptors but does however increase brain dopamine levels.