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Gamma aminobutyric acid (GABA) is a naturally occurring amino acid that works as a neurotransmitter in your brain.

Neurotransmitters function as chemical messengers. GABA is considered an inhibitory neurotransmitter because it blocks, or inhibits, certain brain signals and decreases activity in your nervous system.

When GABA attaches to a protein in your brain known as a GABA receptor, it produces a calming effect. This can help with feelings of anxiety, stress, and fear. It may also help to prevent seizures.

As a result of these properties, GABA has also become a popular supplement in recent years. This is partly because it isn’t available from many food sources. The only foods that contain GABA are fermented ones, such as kimchi, miso, and tempeh.

But how well do these supplements work? Read on to learn more about the science behind the potential benefits of GABA supplements.

GABA’s natural calming effect on the brain has led to countless claims about the use of GABA supplements to reduce stress. Too much stress is linked to poor sleep, a weaker immune system, and a higher risk of depression, among other things. Here’s a closer look at the effects of stress on your body.

In addition, people with certain medical conditions may have lower levels of GABA. Some of these conditions include:

Some people with these conditions take GABA supplements to help manage their symptoms. While this makes sense in theory, there hasn’t been much evidence to suggest that GABA supplements can help with these conditions, aside from anxiety.

Not much is known about the effectiveness of GABA supplements. In fact, experts don’t know how much GABA actually reaches the brain when consumed as a supplement or food. But some research suggests that it’s only small amounts.

Here’s a look at some of the research behind GABA’s more popular uses.


According to a 2006 article, two very small studies found that participants who took a GABA supplement had increased feelings of relaxation during a stressful event than those who took a placebo or L-theanine, another popular supplement.

The article also notes that the relaxing effects were felt within an hour of taking the supplement.

High blood pressure

Some small, older studies have evaluated the use of GABA-containing products for lowering blood pressure.

In one study from 2003, daily consumption of a fermented milk product that contained GABA reduced blood pressure in people with slighted elevated blood pressure after two to four weeks. This was compared with a placebo.

A 2009 study found that taking a GABA-containing Chlorella supplement twice a day reduced blood pressure in those with borderline hypertension.


In a small 2018 study, participants who took 300 milligrams (mg) of GABA an hour before going to bed fell asleep faster than those taking a placebo. They also reported improved sleep quality four weeks after starting treatment.

Like many other studies looking at the effects of GABA supplements in humans, this study was very small, with only 40 participants.

Stress and fatigue

A 2011 study in Japan examined the effects of a beverage containing either 25 mg or 50 mg of GABA on 30 participants. Both beverages were linked to reduced measures of mental and physical fatigue while doing a problem-solving task. But the beverage containing 50 mg appeared to be slightly more effective.

Another study from 2009 found that eating chocolate containing 28 mg of GABA reduced stress in participants performing a problem-solving task. In another study, taking capsules containing 100 mg of GABA reduced measures of stress in people completing an experimental mental task.

The results of all of these studies sound promising. But most of these studies were very small and many are out of date. Larger, more long-term studies are needed to fully understand the benefits of GABA supplements.

The potential side effects of GABA supplements haven’t been properly studied, so it’s hard to know what to expect.

Some commonly reported side effects include:

  • upset stomach
  • headache
  • sleepiness
  • muscle weakness

Since GABA can make some people sleepy, you shouldn’t drive or operate machinery after taking GABA until you know how it affects you.

It’s also not clear whether GABA interacts with any medications or other supplements. If you want to try GABA, consider talking to a doctor first.

Make sure to tell them about any prescription or over-the-counter medications you take, including herbs and other supplements. They can give you a better idea of potential interactions to watch for while taking GABA.

GABA has an important role in our bodies as a chemical messenger. But when used as a supplement, its role is less clear.

Some research shows that it may be an option to help reduce stress, fatigue, anxiety, and insomnia. But many of these studies are small, outdated, or both. More evidence is needed to better understand the potential benefits of taking GABA.

GABA supplements, which you can buy online, may be worth a shot if you’re looking for natural stress relievers. But don’t rely on it to treat any underlying conditions, including severe anxiety, seizure disorders, or high blood pressure.