GABA Calm is a combination of L-Theanine and GABA, two naturally occurring agents that have been shown to support positive mood, relaxation , and relieve mental tension. L-Theanine is an amino acid found in green tea, which has been used for centuries to promote relaxation. GABA (gamma-aminobutyric acid) is the primary inhibitory neurotransmitter in the CNS. Healthy levels of GABA have been associated with relaxation and positive mood.