Neurotransmitter
GABA
Also known as: Gamma-Aminobutyric Acid
The primary inhibitory neurotransmitter responsible for reducing neuronal excitability and promoting calmness.
KÖGN Health grades GABA as B (Moderate evidence) and rates it 3.7 out of 5.
Last reviewed · June 2026
Primary effects
- Reduced anxiety
- Improved relaxation
- Stress reduction
How it works
Reduces neural activity, promoting relaxation and reducing stress.
Overview
GABA plays a central role in calming the nervous system, but oral supplementation has limited ability to cross the blood-brain barrier. As a result, its direct cognitive effects may be less pronounced than expected. However, it can still support relaxation and stress reduction indirectly, particularly when combined with other compounds that enhance its activity.
The evidence
GABA is the brain's main inhibitory neurotransmitter, which is why oral GABA is marketed for relaxation. The catch is mechanistic: it is doubtful that swallowed GABA crosses the blood-brain barrier in meaningful amounts. A review found only weak evidence of a calming effect, much of it from studies with industry conflicts of interest, and any benefit may be placebo or an indirect gut-nerve signal.
How to dose it
Supplements commonly provide 100–800 mg; trial doses vary, and the dose-response is unclear given the uncertainty about how (or whether) it reaches the brain.
When to take it
Acute — taken for short-term calming.
Safety & side effects
Generally well tolerated; occasional tingling or mild drowsiness at higher doses.
Who should avoid it
Few safety issues, but set expectations low — the evidence that oral GABA does much is weak. Take care combining it with sedatives or blood-pressure medication, and discuss with a clinician in pregnancy.
References
Related ingredients
Graded entries that target the same cognitive goals.
Categories
Draft — the dose, safety and evidence notes on this entry were prepared from the published literature and are pending editorial and clinical review.
Educational information, not medical advice. The evidence grade is KÖGN’s editorial assessment of published research, not a health claim. Speak to a qualified clinician before changing what you take.