The Research On GABA & Sleep: How Much To Take + How It Works*
GABA is a funny-sounding neurotransmitter that our bodies naturally release to help us calm down and rest. These days, you can also find GABA supplements that are designed to promote faster, deeper sleep.* Here's what the research says on how supplemental GABA affects sleep, what to know before taking it, and how to find your ideal dose.*
What is GABA?
Gamma-aminobutyric acid (GABA) is the human brain's main inhibitory neurotransmitter1. This non-protein amino acid neurotransmitter balances out excitatory neurotransmitters like glutamine to help get the body into a calm state.*
Our brains are filled with GABA receptors. When activated, these receptors trigger a chain reaction that reduces neural firing and brain cell activity. "GABA interaction with its receptors increases the threshold for cells to become reactive. It relaxes the cells and inhibits reactivity," explains integrative neurologist Ilene Ruhoy, M.D., Ph.D..
When this happens, our stress response dulls, our brains quiet down, and we slip into rest and relaxation mode. Exercising, eating a healthy diet, and practicing relaxation techniques are all ways to support healthy GABA levels in the body naturally. For times when you want to activate this calming response on demand—say, right before bed—you can also take a targeted source: supplemental GABA.*
While endogenous (naturally produced) GABA is more effective at activating inhibitory brain receptors, there is promising evidence that supplemental GABA can also cross the blood-brain barrier and contribute to a relaxation response, making it easier to fall asleep and stay asleep.* Though, as concluded in a 2020 systemic review1, more research is needed since there have been variable study designs and some with small sample sizes in clinicals testing GABA supplements and sleep.
GABA benefits for sleep
Here is what researchers have discovered so far about how GABA supplements might affect sleep:
It may help relax the brain and ease stress.
To study how supplemental GABA affects brain activity, researchers out of Japan2 had 13 people drink plain water, water with PharmaGABA® (100 mg), and water with L-theanine. (PharmaGABA® is a branded version of GABA that's been well studied). They then waited 60 minutes and looked at their brains under an electroencephalogram (EEG) scan. In time, GABA had significantly increased their alpha brain waves (relaxing) and decreased their beta waves (energizing) compared to water or L-theanine.*
In a follow-up study from the same investigation2 on eight people with a fear of heights, the team found that participants who took a GABA supplement were able to stay more relaxed—as shown by the stress indicator salivary IgA—than those who took a placebo when walking across an elevated suspension bridge.*
It may decrease the amount of time it takes to fall asleep.
Separate research out of Japan3 found that GABA, also in the PharmGABA® form, had beneficial effects on sleep when paired with Apocynum venetum (aka rafuma) leaf extract, a popular plant in traditional Chinese medicine.* Its most significant impact was on sleep latency, or the time it takes to fall asleep, which it reduced by 5.3 minutes on average.*
It may increase the amount of time spent in REM sleep.
Beyond helping us fall asleep slightly faster, GABA may also increase the amount of time we spend in deep sleep.* A 2016 study4 found that, compared to a placebo, a PharmGABA® supplement both decreased sleep latency and increased time spent in REM sleep, an essential phase for recovery and memory consolidation, according to an EEG scan.* Follow-up questionnaires revealed that these sleep improvements were significant enough for participants to feel, note the impact.*
This clinical trial also proved that GABA in the supplemental form was effectively and quickly absorbed (peaking in the blood at 30 minutes after ingestion).
What to know about dosage
Using this existing research as a guide, 100 milligrams of GABA5 is the most commonly studied (and thus, scientifically supported) supplemental dose and should be effective for most seeking sleep support.* However, everyone is different. Naturopathic sleep doctor Catherine Darley, N.D., notes that if you don't notice an effect with 100 milligrams, you can increase the dose up to 200 milligrams, while Ruhoy has seen even higher doses—up to 500 milligrams under the supervision of a healthcare practitioner.
As such, "it is recommended that each individual speaks to their doctor first before starting supplementation to obtain guidance," Ruhoy notes.
Your dose will also depend on the type of GABA supplement you are taking. The majority of clinical trials on supplemental GABA and sleep have focused on PharmaGABA®, a naturally sourced form of GABA that is produced through a fermentation process.*
What time of day should it be taken?
The best time to take GABA for sleep will also likely vary from person to person. But again, we can look to the research for indicators.
The clinical trial that tested GABA's calming impact2 on the brain found that it had activated slower brainwaves after 60 minutes, suggesting that taking a supplement an hour before bed will be effective.* However, the 2016 sleep research4 found that it can kick in even faster, reaching its highest level in the blood after only 30 minutes. Whether that blood peak timing corresponds to the sleep-supportive effects (or that comes a bit after) is not known and likely varies from person to person.
As with many sleep supplements, you'll want to tailor the timing of this one to your unique sleep needs. Those who have trouble falling asleep may want to take it earlier in the evening, within a one- to two-hour window, while those who have trouble staying asleep might opt to wait until closer to bedtime.
What to look for in a GABA supplement
Any good supplement starts with high-quality, research-backed ingredients that are present in doses that have been clinically shown to work (in this case, at least 100 milligrams). With sleep supplements, in particular, you'll want to look for one with active ingredients that have been researched in humans and shown to be gentle on the stomach (midnight bathroom wakeups are no fun) and comes in a form that is enjoyable to take and easy to fit into your wind-down routine. (We did the legwork and found 9 that fit the bill.)
Supplements that combine GABA with other relaxing minerals and botanicals may also be effective (perhaps incrementally so given their synergistic actions) for sleep.* Darley notes that GABA combined with L-theanine has been shown to help sleep in animal research6 and her clinical experience.* Magnesium is another sleep supporter that binds to GABA receptors in the brain7, making it a clear pairing for GABA.* (Hence why mindbodygreen chose to include both GABA and magnesium bisglycinate in our sleep formula, sleep support+).*
Possible side effects
Ruhoy notes that in her experience, "GABA is usually well tolerated, but some have reported fatigue, leg discomfort, difficulty focusing, weight gain, and constipation" with the supplement.
"Because GABA can slightly lower blood pressure and acts on neurotransmitters, people on blood-pressure-lowering medications or antidepressants should be cautious," adds Darley.
mbg's VP of scientific affairs, Ashley Jordan Ferira, Ph.D., RDN concludes that, "GABA, and PharmaGABA® specifically, has a strong safety profile, so while side effects or interactions are possible for certain individuals, that would be uncommon."
Ferira goes onto share that, "In the scientific literature8, a small subset of study participants report experiencing mild GI discomfort, while even fewer may experience headache. Still others report drowsiness, which might be viewed by some as a helpful benefit for sleep, not a side effect."
As always, those who are pregnant or breastfeeding should use extra caution when starting the supplement and be sure to consult a doctor first, as GABA supplements haven't been researched in these life stages.
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- Ashley Jordan Ferira, Ph.D., RDN is Vice President of Scientific Affairs at mindbodygreen.
- Ilene Ruhoy, M.D., Ph.D., is a board-certified neurologist practicing integrative pediatric and adult neurology in Seattle.
- Catherine Darley, N.D., is a naturopathic sleep doctor.
Considering how hard it can be to get high-quality sleep night after night, there are now tons of products geared toward helping us fall asleep faster and stay asleep longer. GABA supplements are one option that may be effective when dosed and timed properly.* To further promote great sleep, be sure to leave yourself enough time to wind down, avoid stimulating foods and activities before bed, and keep your bedroom cool, quiet, and dark.
Emma Loewe is the Sustainability and Health Director at mindbodygreen and the author of Return to Nature: The New Science of How Natural Landscapes Restore Us. She is also the co-author of The Spirit Almanac: A Modern Guide To Ancient Self Care, which she wrote alongside Lindsay Kellner.
Emma received her B.A. in Environmental Science & Policy with a specialty in environmental communications from Duke University. In addition to penning over 1,000 mbg articles on topics from the water crisis in California to the rise of urban beekeeping, her work has appeared on Grist, Bloomberg News, Bustle, and Forbes. She's spoken about the intersection of self-care and sustainability on podcasts and live events alongside environmental thought leaders like Marci Zaroff, Gay Browne, and Summer Rayne Oakes.