Quick Summary
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What does GABA do and do supplements work?
GABA (gamma-aminobutyric acid) is a natural "inhibitory neurotransmitter," meaning it blocks impulses between the nerve cells, resulting in a calming effect. Many medications for insomnia, stress and anxiety, epilepsy, and other conditions work by affecting GABA activity. However, taking GABA as supplement does not significantly increase GABA levels in the brain and has not been shown to provide much benefit for epilepsy, insomnia or stress, or cognitive performance, and the effects, if any, are temporary. GABA also affects processes that control blood pressure and muscle mass, so it has been evaluated for hypertension and muscle building (see What It Does). -
What dose of GABA is used?
In clinical trials, GABA has typically been taken at a dose of 100 to 800 mg per day, although higher and lower doses have been used (see Dosage). -
What did CL's tests and review of GABA supplements show?
In laboratory testing, all of the products were shown to provide their listed amounts of GABA without any significant contamination with heavy metals, such as lead. However, the cost to obtain 250 mg of GABA ranged widely, from just 1 cent to $1.60, although higher cost does not mean higher quality or, necessarily, higher likelihood of benefit (see What CL Found and How Products Were Evaluated). 
What is the best GABA supplement?
Among 11 CL Approved products, CL selected Top Picks for low, medium, high, and very high-dose GABA, representing good quality and value.-
How to take GABA?
GABA should be taken with water and need not be taken with food. As any therapeutic effects appear to be temporary, take within one hour of expected benefit. As GABA may directly irritate the throat if taken as a liquid at high dosage, capsules may be preferred to dissolving tablets, liquids, and powders stirred in liquids (see ConsumerTips: How to Take). -
GABA safety and side effects:
At doses of 300 mg or more, mild side effects, such as abdominal discomfort, headache and drowsiness, have been reported. As GABA may lower blood pressure, it may be unsafe to use with blood pressure-lowering drugs. The long-term safety of GABA supplements remains uncertain (see Concerns and Cautions).
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