If you have ever lain awake running through tomorrow's to-do list, you have probably come across ashwagandha. It is one of the most popular herbs for sleep support, and its botanical name, Withania somnifera, even comes from the Latin word for sleep-inducing.
But a name is not evidence. So does ashwagandha actually help you sleep? Here is what the clinical trials show, how strong the evidence is, and how to use it sensibly.
How ashwagandha might affect sleep
Ashwagandha is an adaptogen, an herb thought to help the body handle stress. Researchers have proposed a few ways it might support sleep. The first is through stress: several trials have linked ashwagandha to lower perceived stress and lower levels of cortisol, a hormone that tends to keep you alert (Chandrasekhar et al., 2012). Because a busy, stressed mind is one of the most common barriers to good sleep, easing stress may make it easier to wind down.
The second is a possible direct effect. Laboratory research has identified a compound in ashwagandha leaves called triethylene glycol that promoted sleep in animal studies, and some withanolides may interact with GABA, a calming signal in the brain. These mechanisms are still being studied and have not been confirmed in people.
What the trials found
The best overview comes from a 2021 systematic review and meta-analysis that pooled five randomized, placebo-controlled trials with 400 participants (Cheah et al., 2021). Ashwagandha was linked to a small but statistically significant improvement in overall sleep compared with placebo. The effect was more noticeable in people with greater sleep difficulty at the start, at doses of 600 milligrams a day or more, and when it was taken for at least eight weeks. Participants also reported feeling more mentally alert on waking and less stressed.
Individual trials help fill in the picture. In a 2019 randomized trial, adults with and without significant sleep complaints took 600 milligrams of a root extract a day or placebo for 10 weeks (Langade et al., 2019). Those taking ashwagandha took less time to fall asleep and spent a greater share of time in bed actually sleeping, measured with a wrist-worn activity monitor, along with better sleep quality scores.
A 2020 trial in healthy adults with self-reported poor sleep found that 120 milligrams a day of a different extract for six weeks was linked to better sleep quality scores and faster sleep onset than placebo (Deshpande et al., 2020). And in adults aged 65 to 80, 12 weeks of ashwagandha was linked to better sleep quality and quality-of-life scores, with good tolerability (Kelgane et al., 2020).
How strong is the evidence?
It is promising but not definitive. The trials are randomized and placebo-controlled, which is good. But they are relatively small, most last eight to 12 weeks, several used different extracts and doses, and many were funded by extract manufacturers. The meta-analysis authors rated the overall effect as small. That is a fair summary: ashwagandha appears to offer modest sleep support for many people, particularly those whose sleep is affected by stress, rather than working like a sleeping pill.
That honesty is useful. If you go in expecting gradual improvements over several weeks, rather than knocking you out on night one, you are more likely to give it a fair trial.
How much and how long
Most sleep trials used 120 to 600 milligrams a day of a standardized root extract, and the meta-analysis found larger effects at 600 milligrams or more (Cheah et al., 2021). Always follow the amount on your product label, since extracts differ in strength.
Plan on at least six to eight weeks of consistent daily use before deciding whether it helps. The NIH's National Center for Complementary and Integrative Health notes that ashwagandha may be safe for up to about three months, and that long-term safety is not well established (NCCIH).
When to take it for sleep
Many people take ashwagandha in the evening, an hour or two before bed, as part of a wind-down routine. Others take it in the morning for daytime stress support and still notice better sleep, since its effects appear to build over time rather than peaking right after a dose. Our guide to the best time to take ashwagandha compares the options.
Pairing it with magnesium
Ashwagandha and magnesium are a popular evening pairing. They work through different pathways, and there is no known interaction between them for healthy adults. Magnesium has its own research on sleep quality, which we cover in magnesium for sleep. If you are deciding between the two, our article on whether to take magnesium for sleep or stress may help.
Sleep habits still matter most
No supplement replaces the basics. Consistent sleep and wake times, morning daylight, a cool, dark bedroom, limiting screens before bed, and cutting off caffeine early in the day all make a big difference. Our free sleep cycle calculator helps you plan a bedtime that lines up with natural sleep cycles, and our caffeine cutoff calculator can show when your last coffee should be. Our article on sleep and memory consolidation explains why good sleep matters so much for your brain.
Who should skip it
Ashwagandha is not for everyone. Avoid it if you are pregnant, and talk with your healthcare provider if you are breastfeeding, since safety information is limited (NCCIH). It may affect thyroid hormone levels, and rare cases of liver problems have been reported. It may also add to the effects of sedative medications and interact with medications for thyroid, blood sugar, blood pressure and immune conditions. If you take any prescriptions or have ongoing health concerns, check with your healthcare provider first.
If your sleep problems are persistent, severe, or come with symptoms such as loud snoring, gasping during sleep, or extreme daytime sleepiness, see a healthcare provider rather than relying on supplements.
What to look for in a product
Choose a standardized root extract that lists the amount per serving and the withanolide content, ideally with third-party testing. Be cautious with blends that combine many herbs at undisclosed amounts, since you cannot tell how much ashwagandha you are actually getting.
The evidence at a glance
A meta-analysis of five randomized trials linked ashwagandha to a small improvement in sleep, with larger effects at 600 milligrams a day or more over eight weeks (Cheah et al., 2021). Individual trials linked it to faster sleep onset and better sleep efficiency (Langade et al., 2019), better sleep quality in healthy adults (Deshpande et al., 2020) and in older adults (Kelgane et al., 2020), and lower stress and cortisol (Chandrasekhar et al., 2012).
The bottom line
Ashwagandha does appear to help many people sleep somewhat better, especially when stress is part of the problem, but the effect is modest and builds over weeks. Combine it with good sleep habits and give it a fair trial. Our Ashwagandha is an easy addition to an evening routine, and it pairs naturally with our Magnesium Glycinate.
References
- Chandrasekhar et al. (2012). 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. doi.org/10.4103/0253-7176.106022
- Cheah et al. (2021). Effect of Ashwagandha (Withania somnifera) extract on sleep: A systematic review and meta-analysis. PLOS ONE. doi.org/10.1371/journal.pone.0257843
- Langade et al. (2019). Efficacy and Safety of Ashwagandha (Withania somnifera) Root Extract in Insomnia and Anxiety: A Double-blind, Randomized, Placebo-controlled Study. Cureus. doi.org/10.7759/cureus.5797
- Deshpande et al. (2020). A randomized, double blind, placebo controlled study to evaluate the effects of ashwagandha (Withania somnifera) extract on sleep quality in healthy adults. Sleep Medicine. doi.org/10.1016/j.sleep.2020.03.012
- Kelgane et al. (2020). Efficacy and Tolerability of Ashwagandha Root Extract in the Elderly for Improvement of General Well-being and Sleep: A Prospective, Randomized, Double-blind, Placebo-controlled Study. Cureus. doi.org/10.7759/cureus.7083
- www.nccih.nih.gov/health/ashwagandha
Health & Cognition is not affiliated with the researchers, institutions or publishers mentioned in this article.
