Gamma-aminobutyric acid (GABA) is a major neurotransmitter widely distributed throughout the central nervous system (CNS). Because too much excitation can lead to irritability, restlessness, insomnia, seizures, and movement disorders, it must be balanced with inhibition. GABA – the most important inhibitory neurotransmitter in the brain – provides this inhibition, acting like a “brake” during times of runaway stress. Medications for anxiety, such as benzodiazepines, stimulate GABA receptors and induce relaxation. Either low GABA levels or decreased GABA function in the brain is associated with several psychiatric and neurological disorders, including anxiety, depression, insomnia, and epilepsy. Studies indicate GABA can improve relaxation and enhance sleep. Both synthetic and natural GABA are available as dietary supplements in the United States. Natural GABA is produced via a fermentation process that utilizes Lactobacillus hilgardii – the bacteria used to ferment vegetables in the preparation of the traditional Korean dish known as kimchi.