The substance gamma-aminobutyric acid (GABA) is a neurotransmitter, a chemical used by the human nervous system to send messages and modulate its own function. GABA acts in an inhibitory manner, tending to cause nerves to “calm down.” Drugs in the benzodiazepine-receptor-agonist (BzRA) family (a family that includes true benzodiazepines such as valium, as well as related drugs such as Ambien or Lunesta) exert their effect by facilitating the ability of GABA to bind to receptor sites in the brain. This in turn leads to relaxation, relief from anxiety, induction of sleep, and suppression of seizure-activity.

Unfortunately, when GABA is taken orally, GABA levels in the brain do not increase, presumably because the substance itself cannot pass the blood-brain barrier and enter the central nervous system.1 For this reason, oral GABA supplements cannot replicate the effect of tranquilizing drugs, even though they work through a GABA-related mechanism. GABA supplements can affect the peripheral nervous system, however, as well as any other part of the body not protected by the blood brain barrier. Some evidence suggests that orally ingested GABA might cause physiological changes that lead to benefit for hypertension.