GABA (gamma-aminobutyric acid) is an amino acid which acts as an inhibitory calming neurotransmitter to regulate brain and nerve cell activity by inhibiting the number of neurons firing in the brain. GABA is referred to as the brain's natural calming agent, and by inhibiting over-stimulation of the brain, GABA may help promote relaxation and ease nervous tension. Taken at bedtime, supplemental GABA may assist some people in the initiation of sleep and produce a deeper and more beneficial sleep.

Gamma-aminobutyric acid (GABA) is major neurotransmitter widely distributed throughout the central nervous system (CNS). This neurotransmitter appears to have a significant influence on the pituitary gland's hormone secretion, primarily through its hypothalamic effect.