What is ashwagandha? A plain-English guide

Ashwagandha is an evergreen shrub that grows in parts of India, Africa and the Middle East [7]. Its scientific name is Withania somnifera [9].

People have used it as a medicinal plant for thousands of years, especially in traditional Ayurvedic medicine [7]. Health Canada lists it as an adaptogen, a herbal medicine term for a plant said to help the body resist stress over time [9].

Most supplements contain an extract made from the root, the leaf, or both [7].

NCCIH, part of the US National Institutes of Health, says ashwagandha supplements are often promoted for stress, sleep, male fertility and sports performance [7].

NCCIH's page, last updated in March 2023, said there was not enough evidence to tell whether ashwagandha helps cognitive function or athletic performance [7].

Most studies below compared ashwagandha with a placebo, a dummy pill with nothing active in it. A meta-analysis combines the results of many trials.

Does ashwagandha lower stress?

Evidence grade for perceived stress: B, moderate. Why this grade

The evidence is mixed. A 2022 meta-analysis pooled 12 trials of stress and anxiety in 1,002 adults aged 25 to 48 [1]. Compared with a placebo, ashwagandha lowered stress scores [1]. But results varied a lot from trial to trial, and the authors rated the certainty of the evidence low [1].

A 2025 meta-analysis looked only at trials that lasted at least 2 weeks and used at least 250 mg a day [2]. Across six trials, it found no clear effect on how stressed people felt [2]. Cortisol, a stress hormone, fell when it pooled the seven trials that measured it [2].

Does ashwagandha help with sleep?

Evidence grade for sleep quality: B, moderate. Why this grade

A 2021 meta-analysis of 5 trials with 400 adults found a small improvement in overall sleep compared with a placebo [3]. The effect was larger in adults diagnosed with insomnia, at 600 mg a day or more, and in trials of 8 weeks or more [3]. Results in people with insomnia may not apply to healthy adults. All five trials were run in India, and one was partly paid for by the product's maker [3].

In a six-week trial, 150 healthy adults with unrefreshing sleep got ashwagandha or a placebo by chance [4]. Neither they nor the researchers knew who got which [4]. The extract's maker, Arjuna Natural, is listed as the study's funder [4]. Self-rated sleep quality rose 72% with ashwagandha and 29% with the placebo [4]. Wrist-worn monitors showed longer total sleep time and less time to fall asleep than with the placebo [4].

Does ashwagandha help build strength with training?

Evidence grade for strength and power output: C, limited. Why this grade

Possibly, but the evidence is weak. A 2026 meta-analysis pooled 3 trials with 161 healthy adults who did weight training [5]. Compared with a placebo, ashwagandha was linked to bigger gains in the most weight lifted once, on bench press and lower-body lifts [5].

Under a stricter math check, both results lost statistical significance, meaning they could have been due to chance [5]. They rated their certainty low [5]. They concluded that current evidence does not show that ashwagandha meaningfully improves training gains [5]. The review reports that all three pooled trials were funded or supplied by ashwagandha makers [5].

Our page on how we grade evidence explains what each grade means.

Table: Doses used in studies (not a recommendation)

The rows cover different products, from extracts to dried root, so the amounts do not compare directly [4][9]. These are amounts used in research or set out for product licensing, not advice for anyone. Talk to a clinician before trying any supplement.

NCCIH says ashwagandha may be safe in the short term, up to 3 months [7]. It says there is not enough information to judge long-term safety [7]. The 2021 sleep review also found that data on serious side effects are limited [3].

NCCIH reports that ashwagandha products may cause drowsiness, stomach upset, diarrhea and vomiting [7]. Health Canada requires licensed products to carry a label caution about drowsiness for people who drive or use machines [9]. Australia's medicines regulator, the TGA, has warned that some people get sudden and possibly severe gut symptoms [10].

Liver injury is the main safety concern. LiverTox, an NIH liver-safety reference, says ashwagandha has been linked to cases of liver injury [8]. NCCIH describes these cases as rare [7].

A 2026 review of 25 published patients found that liver injury usually appeared after weeks of use [6]. Most patients recovered after stopping and receiving supportive care, usually over weeks to months [6]. One person needed a liver transplant [6]. Three people who already had cirrhosis, a badly scarred liver, died [6].

In a July 2026 alert, the TGA said liver injury cases are still being reported [10]. Since 2024, it has had 4 more reports of possible liver injury [10]. All 4 people recovered after stopping [10].

NCCIH reports that ashwagandha might interact with some medicines [7]. These include medicines for diabetes, blood pressure and thyroid hormone, plus sedatives, anti-seizure medicines and medicines that lower the immune response [7].

If you take any of these medicines, talk to your doctor or pharmacist before combining them with ashwagandha.

• People who are pregnant or breastfeeding. NCCIH says ashwagandha should be avoided during pregnancy and not used while breastfeeding [7]. Health Canada requires labels to tell people to ask a health care provider first [9].
• People with current or past liver disease. The TGA advises that people who have or have had liver problems avoid it [10].
• People with thyroid or autoimmune conditions, or who are about to have surgery. NCCIH does not recommend ashwagandha for these groups [7].
• People with hormone-sensitive prostate cancer. NCCIH says they should avoid it [7].