Gamma-Aminobutyric Acid

Gamma-Aminobutyric Acid

Other names: GABA; GABA-A GABA-B.

Description:

An amino acid.

Mechanism of action:

GABA is an amino acid which functions as the main inhibitory neurotransmitter in the central nervous system. It is packaged in synaptic vesicles and released into synaptic cleft to target GABA receptors on the postsynaptic surface [2].

Interestingly, it has long been believed that GABA is unable to pass the blood-brain barrier (BBB).

Common indications/uses:

Improve cognition/mental focus

Anxiety management and stress reduction

Promote relaxation and sleep agent

Anti-hypertensive

Dosing:

GABA 50–100 mg/day.

Evidence:

Anti-anxiety: One study reported reduced heart rate variability and salivary chromagin A, a salivary catecholamine marker, during an arithmetic task compared to a control group after administration of GABA-enriched chocolate. A second study reported reduced salivary cortisol and Cga during a psychological stress-inducing arithmetic task. In another study, participants who consumed 50 mg of GABA reported less psychological fatigue after task completion compared to placebo. However, this evidence is questionable as many of these authors are affiliated with the company producing the GABA supplement.

Relaxation and sleep: A randomized double-blind, placebo-controlled study sought to examine the impact of GABA on sleep in 40 patients with insomnia. After 4 weeks of GABA supplementation, sleep latency was decreased and sleep efficacy was increased as compared to placebo.

Anti-hypertensive: In a double-blind, placebo-controlled study examining the effect of GABA on blood pressure in 177 participants, results revealed a reduction in average systolic blood pressure by 4.6 mmHg in the GABA treated groups as compared to the control groups. Multiple other studies have also noted a small reduction in systolic blood pressure.

The currently held belief is that GABA is unable to cross the blood-brain barrier, but there have been a few recent studies revealing conflicting evidence, implying it may potentially be able to cross the barrier in small amounts.

Safety concerns:

Caution is advised for pregnant and lactating women since GABA can affect neurotransmitter and the endocrine system.

Adverse reactions:

No serious adverse events have been associated with GABA intake with up to 120 mg for 12 weeks. Mild side effects include abdominal discomfort, headache, drowsiness, and transient burning sensation in the throat.

Drug interactions:

As GABA is associated with a small reduction in blood pressure, it may work synergistically with anti-hypertensive medication.