Gamma Aminobutyric Acid (GABA) Clinical Evidence


Abdou A, et al. Relaxation and immunity enhancement effects of Gamma -Aminobutyric acid (GABA) administration in humans. 2006:26:201-8.

What are the effects of Gamma-aminobutryric acid (GABA) on relaxation and immunity?

GABA is a neurotransmitter that inhibits the firing of neurons and is considered a natural tranquilizer.

Study Type:
Human clinical intervention trial

Study Design:
Placebo-controlled. In the first phase of the study, researchers measured the brain waves of healthy subjects after they took GABA, L-Theanine or a placebo at baseline, and 30 and 60 minutes post-dose.In the second phase, subjects with acrophobia (fear of heights) took either GABA or a placebo and then crossed a suspension bridge. Levels of immunoglobin A (an antibody) in their saliva were measured during the stressful event.

13 healthy Japanese subjects and 8 acrophobic subjects

A single dose of 100 mg of GABA, 200 mg of Ltheanine or placebo

Alpha waves increased by approximately 50% and beta waves decreased by more than 50% in the healthy subjects. (Alpha waves indicate a state of relaxed alertness. Beta waves are generated during logical thought or when encountering new stimuli, but too much beta wave activity can indicate panic.) In the acrophobic group, IgA levels fell under stressful circumstances when subjects took a placebo. However, when they took GABA, IgA levels were significantly higher.

GABA could work effectively as a natural relaxant and its effects could be seen within 1 hour of its administration and diminish anxiety. Moreover, GABA administration could enhance immunity under stress conditions.

Gamma-aminobutryric acid (GABA) Mechanism of Action

The most important inhibitory neurotransmitter in the brain, GABA functions by modulating nervous system activity and rates of neurotransmission. The GABA-A receptor regulates neuronal excitability and rapid changes in fear arousal, such as anxiety, panic, and the acute stress response.

GABA has been found to increase alpha brain waves (associated with states of relaxation) and decrease beta brain waves (associated with intense focus, anxiety and increased brain activity). GABA may also exert an anti-stress effect by increasing levels of the antibody IgA (immunoglobulin A) in saliva, a parameter of immune function.

Natural Pharma GABA may have better bioavailability than synthetic forms of GABA because it may be better able to cross the blood-brainbarrier, where it exerts its calming effects.