L-Theanine is a natural phytochemical found in Japanese green tea. L-Theanine is a non-essential amino acid that is present in the brain and is a close relative of Glutamate. Studies indicate that L-Theanine interacts with the neurotransmitter, GABA (Gamma-Aminobutyric Acid). GABA, known for its importance in nervous system functioning, works with the mood centers of the brain. Studies in Japan show that L-Theanine helps support the body's ability to deal with PMS and occasional, everyday anxiety.

L-Theanine is a unique amino acid found almost exclusively in the green tea plant (Camellia sinensis) and is the primary ingredient contributing to the unusual taste of green tea. Animal studies have shown that L-Theanine crosses the blood brain barrier, increases dopamine and GABA levels in the brain, and inhibits the stimulatory properties of caffeine. Human studies have shown that taking L-Theanine results in the emission of brain waves associated with a state of relaxation.