What is it?
GABA (gamma-aminobutyric acid) is an amino acid that the body does not use to build proteins. It is the main inhibitory, or calming, chemical messenger in the brain, and it occurs naturally in plants, animals and microbes and in foods, especially fermented foods. Commercial GABA is usually made by bacterial fermentation. It is sold as a dietary supplement and has been studied for blood pressure, sleep and stress. In cosmetics it is listed as a hair conditioning ingredient.
Key information
- A 2021 safety review by the U.S. Pharmacopeia found no serious adverse events with GABA at up to 18 grams a day for 4 days or 120 mg a day for 12 weeks.
- Some studies found a temporary, moderate drop in blood pressure, and USP noted that taking GABA with blood-pressure medicines could increase the risk of low blood pressure.
- Evidence reviewed by USP indicates that very little GABA taken by mouth crosses into the brain.
- FDA has not reviewed GABA's safety: the two GRAS notices submitted for it were withdrawn before review.
More information
GABA is found throughout nature, and fermented foods are especially rich in it; the U.S. Pharmacopeia (USP) cites kimchi, Japanese green tea leaves, cured meats and cheeses. Commercial GABA is mostly made by fermentation with lactic acid bacteria, though it can also be made with enzymes or by chemical synthesis. Labels may call it plant-derived; the molecule is the same whatever the source.
In 2021 USP published a safety review of GABA as a dietary supplement ingredient. It found no serious adverse events in studies of pure GABA at up to 18 grams a day for four days, or in longer studies at up to 120 mg a day for 12 weeks. In short studies at several grams a day, a few people felt a slight burning in the throat. Some studies found a temporary drop in blood pressure of 10 percent or less, so USP noted that combining GABA with blood-pressure medicines could increase the risk of low blood pressure. Rats and dogs given up to 1 gram per kilogram of body weight a day long term showed no toxicity. There were no studies in pregnancy or breastfeeding, and USP advised caution there because GABA can affect hormones such as prolactin. A 2026 rat study, written by company-employed authors with the experiments run by independent contract laboratories, found no effects on fertility or offspring at up to 2,500 mg/kg a day.
Evidence reviewed by USP indicates that very little GABA crosses from the blood into the brain. In the United States GABA is sold as a dietary ingredient, but FDA has not evaluated its safety; the two GRAS notices submitted for it were withdrawn before review. In cosmetics, the EU lists it as aminobutyric acid, a hair conditioning ingredient, with no restrictions.
Sources: Nutrients (2021), via PMC: United States Pharmacopeia (USP) safety review of gamma-aminobutyric acid (GABA); Toxicology Reports (2026), via PubMed: Repeated oral administration of gamma-aminobutyric acid (GABA) does not cause reproductive or developmental toxicity in rats; European Commission CosIng: Aminobutyric Acid
