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.