GABA vs Ashwagandha: How They Differ for Stress, Calm and Sleep

GABA and ashwagandha both come up when people look for a calmer day, but they work in different ways. GABA is the brain's own calming messenger sold in supplement form, while ashwagandha is an adaptogenic root studied in stressed adults for perceived stress and cortisol over 8 weeks or more of daily use. Here is how they compare and whether you can take them together.

Key Takeaways

• GABA is the brain's main calming messenger, but whether swallowed GABA crosses into the brain is still debated (Boonstra et al., 2015).
• A review of 14 placebo-controlled trials found oral GABA may support stress and sleep, with the clearest sleep results at 100 to 300 mg a day over 1 to 4 weeks (Hepsomali et al., 2020).
• Ashwagandha is a root used in Ayurveda. In stressed adults, 250 or 600 mg a day of root extract for 8 weeks lowered perceived stress scores and cortisol compared with placebo (Salve et al., 2019).
• The two are studied differently: GABA mostly in single doses and short courses, ashwagandha as a daily extract measured after 8 weeks to 60 days.
• Human trials have studied each one on its own. In a lab study, ashwagandha root extract acted on GABA receptors while containing little or no GABA (Candelario et al., 2015).

GABA vs Ashwagandha: The Core Difference

GABA (gamma-aminobutyric acid) is a messenger your brain makes itself. It is the brain's main inhibitory signal, the one that tells nerve cells to quiet down, and it is also sold as a supplement (Boonstra et al., 2015).

Ashwagandha (Withania somnifera) is a root, not a brain chemical. It is known as an adaptogen, a plant studied for how it supports the body's response to everyday stress, and trials have tracked stress questionnaires and cortisol (Chandrasekhar et al., 2012). More on the root is on our ashwagandha root extract ingredient page.

	GABA	Ashwagandha
What it is	The brain's main calming messenger, also sold as a supplement	An adaptogenic root used in Ayurveda, taken as a root extract
Amounts studied	About 2 to 100 mg in stress studies; 100 to 300 mg a day in sleep studies	240 to 600 mg a day of root extract
How long studies ran	Single doses and courses of 1 to 4 weeks	8 weeks to 60 days for stress; 6 to 12 weeks for sleep
What was measured	Heart rate variability, cortisol and other stress markers; time to fall asleep	Perceived stress scores, cortisol and sleep quality
How it is thought to work	Adds the calming messenger itself; how much reaches the brain is debated	Supports the body's stress response; in lab work, root compounds acted on GABA receptors
Common side effects	Drowsiness, stomach discomfort, headache; a short-lived drop in blood pressure	Loose stools, nausea, drowsiness

What GABA Research Shows

The big question for GABA supplements is whether they reach the brain at all. GABA has long been thought unable to cross the blood-brain barrier, the filter that controls what passes from the blood into the brain. Studies on this point disagree, and the reviewers suggest effects might come from some GABA getting through or from signals sent through the nerves of the gut (Boonstra et al., 2015).

A 2020 systematic review gathered 14 placebo-controlled trials of oral GABA. In stress studies using about 2 to 100 mg, some trials recorded changes in markers such as heart rate variability and cortisol, though results varied between studies. For sleep, the clearest results came from 100 to 300 mg a day over 1 to 4 weeks, mostly in people who reported poor sleep, and mainly in how long it took to fall asleep. The authors concluded that GABA may support stress and sleep and called for more research on dose, timing and duration (Hepsomali et al., 2020).

What Ashwagandha Research Shows

Ashwagandha has more daily-use trials. These placebo-controlled studies were run in stressed adults:

Trial	Who and how much	What changed with ashwagandha
Chandrasekhar et al., 2012	64 adults with a history of chronic stress; 300 mg twice a day for 60 days	Lower scores on all stress scales and lower blood cortisol than placebo; side effects mild and similar to placebo
Lopresti et al., 2019	60 stressed, otherwise healthy adults; 240 mg once a day for 60 days	Greater drop in morning cortisol than placebo; no adverse events reported
Salve et al., 2019	60 stressed adults; 250 or 600 mg a day for 8 weeks	Lower perceived stress scores and cortisol at both amounts, and better sleep quality than placebo

In the 8-week trial, the results for stress scores and cortisol were statistically stronger at 600 mg than at 250 mg (Salve et al., 2019). For sleep, the NIH Office of Dietary Supplements summarizes a 2021 analysis that found a small improvement at 250 to 600 mg a day over 6 to 12 weeks, with stronger results at 600 mg and at 8 weeks or longer (NIH ODS, 2025). Our guide to ashwagandha benefits covers the wider research.

Can You Take Ashwagandha and GABA Together?

Human trials have studied ashwagandha and GABA separately, so there is no studied combined amount. The link between them comes from lab work: in frog egg cells fitted with rat brain GABA receptors, an ashwagandha root extract switched on those receptors. The extract contained little or no GABA, so the authors concluded that other root compounds were responsible (Candelario et al., 2015). That is cell research, and it is one reason the two are often discussed together.

Because both list drowsiness among their side effects, start one at a time and talk with your clinician before adding the second, especially if you take any medicine that makes you sleepy.

Choosing Between GABA and Ashwagandha

• For a daily stress routine: ashwagandha is the one studied as a daily extract over 8 weeks to 60 days, with stress scores and cortisol as the main measures.
• For a sleep-focused choice: GABA's clearest results came in sleep studies at 100 to 300 mg a day over 1 to 4 weeks, mainly in how long it took to fall asleep.
• For calm focus during the day: L-theanine, the amino acid in tea leaves, is another option people compare with GABA; see GABA vs L-theanine and ashwagandha vs L-theanine.
• Give ashwagandha time: benefits build with consistent daily use. Months 1 to 2 can bring early changes, and 3 months and beyond is where the full benefit builds.

For a wider view of the options, see best supplements for stress and mood and our stress, mood and nervous system guide.

Safety: What to Know Before You Start

GABA

A safety review by the United States Pharmacopeia found no serious safety concerns at the amounts studied. Pure GABA was given at up to 18 g a day for 4 days without serious adverse events, and longer studies used lower amounts, such as 120 mg a day for 12 weeks. Some studies saw a short-lived, moderate drop in blood pressure that returned to normal a few days after stopping, so the reviewers flagged a possible added effect with blood pressure medicines. Reported side effects included stomach discomfort, headache, drowsiness and, after large 5 g doses, a burning feeling in the throat. There are no studies in pregnancy or breastfeeding (Oketch-Rabah et al., 2021).

Ashwagandha

Common side effects, such as loose stools, nausea and drowsiness, are usually mild. The NIH notes case reports of liver injury, effects on thyroid hormone levels in some studies, and possible interactions with thyroid hormone, diabetes, blood pressure, immune-suppressing and sedative medicines. Some experts advise avoiding it during pregnancy (NIH ODS, 2025). Talk to your doctor before taking it if you take any of those medicines or have a liver or thyroid condition. Our guide to ashwagandha side effects goes into more detail.

Where Our Products Fit

We do not sell GABA on its own. Our Forage capsules include ashwagandha root extract 100 mg in every 2-capsule serving, alongside Himalayan shilajit 100 mg and seven 8:1 mushroom fruiting body extracts: lion's mane, cordyceps and reishi at 200 mg each, and chaga, maitake, turkey tail and shiitake at 150 mg each. Suggested use is two capsules daily, taken in the morning with or without food. It is made with third-party tested ingredients in vegan capsules.

If you are drawn to the calm side of this comparison, our Theanine Nasal Spray gives 36 mg of L-theanine in every 2-spray serving, with alkaline water as the only other ingredient. It is absorbed through the lining of the nose instead of being swallowed like a capsule, so some of each dose skips digestion.

Frequently Asked Questions

Is GABA or ashwagandha better for stress?

They are studied in different ways. Ashwagandha has several placebo-controlled trials in stressed adults, where 240 to 600 mg a day of root extract for 8 weeks to 60 days lowered stress scores or cortisol compared with placebo. GABA studies mostly use single doses or short courses, with results that vary between studies. For a daily stress routine, ashwagandha is the better studied of the two.

Can you take ashwagandha and GABA together?

Human trials have studied ashwagandha and GABA separately, so there is no studied combined amount. Both list drowsiness among their side effects, so start with one at a time and see how you respond. Talk with your clinician before combining them, especially if you take sleep aids, sedatives or blood pressure medicine.

Is GABA or ashwagandha better for sleep?

In GABA trials, the clearest sleep results came at 100 to 300 mg a day over 1 to 4 weeks, mainly in how long it took to fall asleep. For ashwagandha, an analysis of trials found a small improvement in sleep at 250 to 600 mg a day over 6 to 12 weeks, with stronger results at 600 mg.

Does ashwagandha increase GABA?

It does not add GABA itself. In a lab study, an ashwagandha root extract switched on GABA receptors even though it contained little or no GABA, which suggests other root compounds act on the same calming system. That finding comes from cells, and human studies of ashwagandha have measured stress scores, cortisol and sleep rather than brain GABA.

Does a GABA supplement reach the brain?

That is still debated. GABA has long been thought unable to cross the blood-brain barrier, and studies on the question disagree and use different methods. Researchers suggest GABA supplements might work through some GABA getting through or through signals from the nerves of the gut, and have called for brain scanning studies to settle it.

Who should not take ashwagandha or GABA?

Talk to your doctor first if you are pregnant or breastfeeding, or if you take thyroid, diabetes, blood pressure, immune-suppressing or sedative medicines, since ashwagandha may interact with them. GABA has caused a short-lived drop in blood pressure in some studies, so take care if you use blood pressure medicine.

Sources

• Boonstra E, de Kleijn R, Colzato LS, Alkemade A, Forstmann BU, Nieuwenhuis S. Neurotransmitters as food supplements: the effects of GABA on brain and behavior. Frontiers in Psychology, 2015. https://pubmed.ncbi.nlm.nih.gov/26500584/
• Hepsomali P, Groeger JA, Nishihira J, Scholey A. Effects of oral gamma-aminobutyric acid (GABA) administration on stress and sleep in humans: a systematic review. Frontiers in Neuroscience, 2020. https://pubmed.ncbi.nlm.nih.gov/33041752/
• Chandrasekhar K, Kapoor J, Anishetty S. A prospective, randomized double-blind, placebo-controlled study of safety and efficacy of a high-concentration full-spectrum extract of ashwagandha root in reducing stress and anxiety in adults. Indian Journal of Psychological Medicine, 2012. https://pubmed.ncbi.nlm.nih.gov/23439798/
• Lopresti AL, Smith SJ, Malvi H, Kodgule R. An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: a randomized, double-blind, placebo-controlled study. Medicine (Baltimore), 2019. https://pubmed.ncbi.nlm.nih.gov/31517876/
• Salve J, Pate S, Debnath K, Langade D. Adaptogenic and anxiolytic effects of ashwagandha root extract in healthy adults: a double-blind, randomized, placebo-controlled clinical study. Cureus, 2019. https://pubmed.ncbi.nlm.nih.gov/32021735/
• Candelario M, Cuellar E, Reyes-Ruiz JM, et al. Direct evidence for GABAergic activity of Withania somnifera on mammalian ionotropic GABAA and GABA rho receptors. Journal of Ethnopharmacology, 2015. https://pubmed.ncbi.nlm.nih.gov/26068424/
• Oketch-Rabah HA, Madden EF, Roe AL, Betz JM. United States Pharmacopeia (USP) safety review of gamma-aminobutyric acid (GABA). Nutrients, 2021. https://doi.org/10.3390/nu13082742
• NIH Office of Dietary Supplements. Ashwagandha: Is it helpful for stress, anxiety, or sleep? Health Professional Fact Sheet, 2025. https://ods.od.nih.gov/factsheets/Ashwagandha-HealthProfessional/

These statements have not been evaluated by the Food and Drug Administration. This content is for education and is not medical advice. Our products are not intended to diagnose, treat, cure or prevent any disease. Talk with a healthcare provider before starting a new supplement if you are pregnant, breastfeeding or taking medication.