Do They Actually Reduce Anxiety?

GABA supplements are available in many forms, including capsules, powder, liquid, and gummies. GABA refers to the amino acid and neurotransmitter Gamma-aminobutyric acid. Neurotransmitters are chemicals responsible for carrying signals from one nerve cell to another. Specifically, GABA changes brain activity, producing a calming effect.

While GABA is a naturally occurring chemical in your brain, it’s also widely available as a supplement. However, in supplement form, only minimal amounts of GABA can actually cross the blood-brain barrier (BBB) and have any effect on the brain.

This article discusses the potential uses, side effects, and interactions of over-the-counter (OTC) GABA supplements.

Note: This article is not about GABA agonists, such as chlormethiazole or Valium (diazepam), which are prescription medications and not OTC supplements.

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Supplement Facts

  • Active ingredient(s): Gamma-aminobutyric acid
  • Alternate name(s): 4-aminobutanoic acid, fermented rice germ extract containing GABA (RFE-GABA), GABA, γ-aminobutyric acid
  • Legal status: Legal OTC supplement in most U.S. states
  • Suggested dose: Varies based on condition
  • Safety considerations: Research on the use in pregnancy and breastfeeding and use in children in progress; may interact with some prescription medications

What Is GABA?

Gamma-aminobutyric acid (GABA) is an amino acid and neurotransmitter that the body naturally produces. GABA is mostly produced in the nervous system but is also made in relatively large quantities by beta cells in the pancreas.

Function of GABA

As a neurotransmitter, GABA sends messages throughout the central nervous system. Because it is an inhibitory neurotransmitter, GABA blocks or inhibits certain nerve transmission, so messages aren’t sent on to other neurons.

This slowdown in message transition may help produce a calming effect and may play a role in controlling anxiety, stress, and fear.

Effects of GABA Supplements

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian nutritionist (RD or RDN), pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.

Like many supplements, people may use GABA for various reasons. However, there are several clinical trials assessing GABA for the following potential uses.

Sleep Quality

In a small study of 40 people with insomnia, 300 milligrams (mg) of GABA one hour before bed for four weeks improved sleep quality by reducing sleep latency (the time it takes to fall asleep). Further, well-designed studies are needed to confirm these results.


A study of 30 people suggested GABA-enriched oolong tea was linked with lower short-term stress scores than regular oolong tea. Larger, well-designed studies are needed to confirm these results.

Authors of a review of 14 studies concluded there is limited evidence that GABA from foods or supplements improves stress. They noted further studies are needed to understand the action of how GABA food sources and supplements work, as well as the amounts required to affect stress reduction and relaxation.

Blood Pressure

There are numerous small studies about GABA’s effects on lowering blood pressure. However, the results are mixed. This may have something to do with each study’s different GABA dosages and dosage forms—like soy sauce, fermented milk, and specific GABA tablets.

What Are the Side Effects of GABA Supplements?

As with many medications and supplements, side effects are possible with GABA.

Common Side Effects

Common side effects of GABA may include:

  • Burning feeling in throat
  • Slight shortness of breath
  • Skin tingling sensation

While common, these side effects tend to go away within a few minutes.

Severe Side Effects

Presently, there are no studies that specifically assess GABA’s safety. But several clinical trials suggest that GABA isn’t linked to severe side effects, except for low blood pressure. You may feel faint with low blood pressure.

Severe allergic reaction is another serious side effect possible with any medication or supplement. If you’re having a severe allergic reaction to GABA, get medical help immediately. Symptoms may include breathing difficulties, itchiness, and rash. 

Call 911 if your symptoms feel life-threatening.


Your healthcare practitioner may advise against using GABA if any of the following applies to you:

  • Severe allergic reaction: If you have a severe allergic reaction to GABA or any of its components (ingredients), you shouldn’t take this medication.
  • Inherited disorders of amino acid metabolism: GABA is an amino acid. It may not be appropriate for people with inherited disorders of amino acid metabolism. Speak with your or your child’s healthcare provider if you have questions before taking supplements.
  • Pregnancy or breastfeeding: There are currently no studies about the effects and safety of GABA during pregnancy. There are also no clinical trials on GABA’s effects and safety in nursing infants. For this reason, take GABA with caution. Speak with your healthcare provider to help you weigh the benefits and risks of GABA while pregnant or breastfeeding. 
  • Children: There is limited information about the effects and safety of GABA in children. Research on GABA in children is in progress. But with most GABA product labels, GABA supplements should only be used in adults.
  • Blood pressure medications: GABA may lower your blood pressure. This may have additive effects with antihypertensives, such as Microzide (hydrochlorothiazide).
  • Adults over 65: In a small randomized-controlled clinical trial of 60 older adults, some participants took GABA in fermented Laminaria japonica (a type of seaweed). While the researchers monitored for side effects, none were mentioned in the study. However, some older adults may generally be more sensitive to medication side effects. For this reason, take GABA with caution.

Dosage: How Much GABA Should I Take?

Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your individual needs.

Because there is limited information about GABA supplements, there are no guidelines on the appropriate dosage for any condition.

To safely take natural medications like GABA, follow the directions on the label and inform your healthcare providers and pharmacists about any medication changes. This includes OTC herbal, natural medicines, and supplements. They can help prevent possible interactions and side effects. They can also ensure that you’re giving GABA a fair trial at appropriate doses.

How to Choose a Supplement

In the United States, the Food and Drug Administration (FDA) does not regulate supplements the way it regulates prescription drugs. That means some supplement products may not contain what the label says. When choosing a supplement, look for third-party tested products (such as the U.S. Pharmacopeia, Consumer Labs, or NSF) and consult a healthcare provider, registered dietitian nutritionist (RD or RDN), or pharmacist. 

What Happens if I Take Too Much GABA?

There is limited information about GABA toxicity and overdoses. Data has shown no serious adverse events associated with GABA at intakes up to 18 grams per day for four days and in longer studies at intakes of 120 milligrams per day for 12 weeks.

However, high daily doses of GABA (5 to 10 grams) may result in a burning sensation in your throat and low blood pressure. The upper recommended intake is typically 3 grams per day—with no more than 750 milligrams per dose.

Talk with your healthcare provider before taking GABA—especially if you’re planning to take at least 300 milligrams per day for more than four weeks.


Use caution when taking GABA with the following:

  • Anti-seizure medications: In general, anti-seizure medications—like phenytoin—work by slowing abnormal activity in the brain. Since GABA also has a similar effect, it may interact with these medications.
  • Blood pressure medications: GABA may lower your blood pressure. This may have additive effects with antihypertensives, such as Microzide (hydrochlorothiazide).
  • Sleep-inducing medications: GABA improved sleep quality in a small randomized-controlled trial of 40 people. This effect may increase when combined with other similar medicines in mice.

It is essential to carefully read a supplement’s ingredients list and nutrition facts panel to know which ingredients and how much of each ingredient is included. Please review this supplement label with your healthcare provider to discuss potential interactions with foods, other supplements, and medications.

Similar Supplements

GABA is an amino acid. Other similar amino acids also available as supplements include:

  • 5-hydroxytryptophan (5-HTP)
  • L-tryptophan

Like GABA, 5-HTP and L-tryptophan have been studied as a potential sleep aid. However, current research doesn’t support 5-HTP and L-tryptophan to help with sleep.

5-HTP and L-tryptophan are also purported to improve mood because they convert into serotonin, a naturally occurring brain chemical that affects mood. However, there is little data to support this use. Theoretically taking these supplements could also cause a condition called serotonin syndrome in which high blood pressure is a symptom.

Sources of GABA and What to Look For

While GABA is available as an OTC supplement, there are other sources of GABA.

Food Sources of GABA

You can get natural sources of GABA through your diet. Examples of GABA-containing foods include:

  • Bok choy
  • Brussels sprouts
  • Cabbage
  • Cauliflower
  • Collard greens
  • Mushrooms
  • Potatoes
  • Rice
  • Soybeans
  • Tomatoes
  • Watercress

Glutamic acid or glutamate is a precursor of GABA, meaning your body can use them to make GABA. Theoretically, increasing foods with glutamic acid or glutamate may increase GABA in the body. Glutamic acid may be obtained by eating meat, poultry, fish, eggs, dairy products, and select high-protein vegetable sources.

Drastic dietary changes may interact with your medications or affect your medical conditions. For this reason, talk with your healthcare provider first. They will help you safely make these changes.

GABA Supplements

GABA is available in many dosage forms, including capsules and tablets. If you have difficulty swallowing pills, GABA is available in the following dosage forms:

  • Chewables
  • Lozenges
  • Liquids
  • Powder

GABA also has vegan or vegetarian products.

Which supplement you choose primarily comes down to your preference and what you hope to get in terms of effects. Each product may work differently depending on the form, so following the directions is essential.

Other Ways to Increase GABA

Mind-body practices might help boost your brain’s GABA levels. One study found practicing yoga and breathing exercises may lead to higher GABA levels. However, further studies are needed to confirm these results.


GABA is an amino acid and neurotransmitter that may help improve your mood and sleep. Several studies show that increased GABA levels in the brain can help decrease anxiety, stress, and depression.

However, very little GABA may cross the blood-brain barrier when taken in oral supplement form. More research is needed to assess GABA’s effectiveness and safety. Before taking GABA, talk with your pharmacist or healthcare provider to help you safely achieve your health goals.


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