GABA
GABA is an inhibitory neurotransmitter sold for calm and sleep. Oral supplements have uncertain brain uptake and mixed evidence.
Overview
What is GABA?
Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the central nervous system.
GABA binds to GABA(A) and GABA(B) receptors in the brain. It is also found in the pancreas, some immune cells and the gastrointestinal tract.
Oral GABA supplementation does not significantly increase brain GABA levels. Most research that suggests a potential calming effect of GABA comes from manufacturer-funded studies.
GABA does not have reliable benefits for sleep. During heat exposure, GABA can lower core body temperature but any benefits for sleep do not appear to be related to this mechanism.
Many foods naturally contain GABA in small quantities including kimchi, walnuts and yogurt.
Dosage
A typical dose of GABA is 75 to 100 mg per day.
For sleep latency, studies typically use a dose of 75-100 mg per day taken 30 to 60 minutes prior to sleep. It is unknown if this dosage is optimal or effective.
Doses of up to 300 mg per day have been used in studies to reduce sleep latency, however this higher dose was only slightly more effective than a 75 mg per day dose, and was more likely to have adverse effects including sedation.
Effect graph
Effect heatmap
SupplementDEX Database
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Database Snapshot
Most gaba research is concentrated in a handful of conditions.
- Sleep accounts for 3 of 8 studies (38%).
- Epilepsy accounts for 2 of 8 studies (25%).
- Stress accounts for 2 of 8 studies (25%).
- Sparse coverage remains for Epilepsy, Stress, Mood.
Dietary Sources
Top dietary sources
Food sources
The absorption profile of GABA supplements and foods containing GABA is similar. To date, there are limited studies demonstrating GABA's ability to permeate the blood-brain barrier in humans, possibly due to a high brain efflux rate.
Sources include Adlay, Adzuki Bean, Alcohol Beverages, Apple, Barley, Bean Sprout, Beans, Broccoli, Brown Rice Germ, Brown Rice Sprout, Buckwheat, Carrot, Cereals, Cheese, Chestnut, Corn, Cruciferous Vegetables, Dairy Products, Fermented Sausage, Green Laver Seaweed, Kale, Kimchi, Lactobacillus, Legumes, Oatmeal, Onion, Potato, Raw Spinach, Rice, Ripe Squash, Sauerkraut, Shiitake Mushroom, Sourdough, Soy Products, Sweet Potato, Teas, Tempeh, Tomatoes, Traditional Asian Fermented Food, Vegetables, White Tea, Wild Cabbage, Wild Celery, Yam, and Yogurt.
Safety
GABA is likely safe when used at dosages of 75 to 300 mg per day for up to one month.
Special populations
Pregnancy & breastfeeding
AvoidThe effects of GABA supplementation are not well studied in pregnant or lactating women, usage should be avoided in these populations.
Children
AvoidThe effects of GABA supplementation in children are not well studied. Usage should be avoided in this population.
Other notes
Studies typically use a dose of around 75 to 100 mg per day. Common side effects from GABA supplementation include drowsiness, headache, nausea and sedation.
Frequently Asked Questions
Takeaway
GABA is a chemical made in the brain that is also found in some foods.
GABA works as an inhibitory neurotransmitter, but oral ingestion does not appear to confer any reliable benefits as GABA cannot effectively cross the blood-brain barrier.
There is limited evidence that oral GABA intake from functional foods or supplements can improve anxiety, sleep or stress.
References
Sources11 references
SupplementDEX uses only high-quality sources to determine supplement effectiveness.
What is GABA
4 references1.Oral GABA supplementation and brain GABA levelsExternal source
2.GABA and potential calming effectsExternal source
3.GABA and thermoregulationExternal source
4.GABA neurons and NREM sleepExternal source
SupplementDEX Database · Sleep
3 references5.SupplementDEX Database: Sleep — Efficacy and Safety of Low-Dose Gamma-Aminobutyric Acid From Unpolished Rice Germ as a Health Functional Food for Promoting Sleep: A Randomized, Double-Blind, Placebo-Controlled Trial2022
In a 4-week double-blind RCT of 54 adults, 75 mg/day GABA from unpolished rice germ improved sleep quality versus placebo as a health functional food.
6.SupplementDEX Database: Sleep — Safety and Efficacy of Gamma-Aminobutyric Acid from Fermented Rice Germ in Patients with Insomnia Symptoms: A Randomized, Double-Blind Trial2018
In a 4-week double-blind RCT of 40 insomnia patients, 300 mg/day GABA from fermented rice germ reduced sleep latency and increased sleep efficiency versus placebo on polysomnography.
7.SupplementDEX Database: Sleep — Effect of oral γ-aminobutyric acid (GABA) administration on sleep and its absorption in humans2016
In a crossover study of healthy adults, oral GABA shortened sleep latency and increased non-REM sleep time on EEG; blood GABA peaked 30 minutes after dosing.
SupplementDEX Database · Stress
2 references8.SupplementDEX Database: Stress — Oral intake of γ-aminobutyric acid affects mood and activities of central nervous system during stressed condition induced by mental tasks2012
In a crossover RCT of 63 adults under mental stress, 100 mg oral GABA reduced alpha-to-beta EEG ratio and improved mood measures versus dextrin placebo during stress tasks.
9.SupplementDEX Database: Stress — Relaxation and immunity enhancement effects of gamma-aminobutyric acid (GABA) administration in humans2006
In two human studies, oral GABA increased alpha waves and decreased beta waves on EEG (suggesting relaxation), and blunted stress-induced immune changes in acrophobic subjects crossing a suspended bridge.
SupplementDEX Database · Epilepsy
2 references10.SupplementDEX Database: Epilepsy — GABA and phosphatidylserine in human photosensitivity: a pilot study1994
In a 3-day study of 9 photosensitive epilepsy patients, a single oral dose of 3,000 mg GABA plus 600 or 1,200 mg phosphatidylserine did not systematically change photosensitivity range.
11.SupplementDEX Database: Epilepsy — Preliminary evaluation of the effect of GABA and phosphatidylserine in epileptic patients1987
In a pilot study of 42 drug-resistant epilepsy patients, combined GABA and phosphatidylserine showed no benefit for partial seizures but produced a dose-related decrease in absence seizures.