GABA (Gamma-aminobutyric Acid) is a naturally occurring (non-essential) amino acid found in your brain, where it plays an important role as a calming neurotransmitter within your central nervous system. It helps your body react to stress and tension. Many people also find GABA supplements helpful in promoting sound sleep and general fitness. While this amino acid is found naturally in some green plants, yeasts, and bacteria, dietary sources are not believed to be sufficient enough to have any significant impact on brain levels. Therefore, GABA supplements are often the best solution to support healthy levels.