Ashwagandha

If you try it, use a standardised root extract (such as KSM-66 at 300–600 mg a day) for a limited period. Avoid it if you have liver, thyroid or autoimmune disease, are pregnant or breastfeeding, or take sedatives, opioids or alcohol.

What it is

Ashwagandha (Withania somnifera) is a shrub whose root, and sometimes leaf, is sold as an extract. It is said to lower the stress hormone cortisol by damping the body's stress-response system. Its active compounds are a family of steroid-like molecules called withanolides.

Stress, anxiety and sleep: modest and uncertain

Pooled trials find modest reductions in stress and anxiety, but the trials are small and short and their results vary widely: a 2022 meta-analysis of 12 trials (about 1,000 people) rated the certainty of the evidence low for both.^[1] Several small trials show better sleep quality and faster sleep onset, mainly in stressed people or people with insomnia.^[2] The US National Institutes of Health calls the sleep evidence suggestive.^[3]

The most reliable anxiety evidence comes from people with diagnosed mental disorders. In 14 small trials in people with anxiety and other mental disorders (about 700 people, a median of 600 mg a day for 8 weeks), it eased anxiety.^[4] A separate pooling of 488 people found it lowered cortisol by about 32 nmol/L, though in that pooling its effect on how stressed people felt was unclear; the diagnosed-disorder review did find less stress.^[5] These trials are small and short.

One animal finding gets quoted as an anti-ageing effect. In aged rats, a leaf extract partly restored the daily rhythm of two of three clock-linked regulators in the brain's master clock, while the core clock gene tested didn't respond.^[6] That is one rat study, with a different part of the plant from the root extracts people take.

For sleep itself, ashwagandha is side help at best: cognitive behavioural therapy for insomnia remains the treatment that works, and other low-risk options are compared on Sleep supplements.

Which extract

Most of the better trials use one of two standardised extracts. KSM-66 is a root-only extract, standardised to about 5% withanolides and dosed at 300–600 mg a day in its trials.^[7] Sensoril is a more concentrated root-and-leaf blend, dosed lower at 125–250 mg a day. Leaf extracts have shown liver toxicity in laboratory cell studies, which is one reason to prefer a root extract.^[8]

The liver risk, and why a good brand is no guarantee

Liver injury from ashwagandha is real. A 2026 review of 25 published cases found no consistent dose pattern, and no basis for blaming poor-quality or leaf-containing products — mostly because the formulation and plant part usually went unrecorded.^[9] In the largest case series, the products involved were chemically clean, single-ingredient extracts.^[10]

Injury is uncommon and usually resolves when the supplement is stopped. Among the 25 published cases most people recovered, but one needed a liver transplant and three people with existing cirrhosis died; the transplant case was a previously healthy woman, so severe injury is not confined to people who were already ill.^[11] Still, Denmark banned ashwagandha in food supplements in 2023,^[12] and EU regulators have recommended a procedure that could lead to an EU-wide ban.^[13]

Who should avoid it, and drug interactions

• Existing liver disease — among published cases were deaths in people who already had cirrhosis, and the authors advise people with advanced chronic liver disease to avoid it.^[14]
• Thyroid disease — it can stimulate the thyroid.^[15]
• Pregnancy and breastfeeding.^[16]
• Autoimmune conditions — commonly advised against, though this page has no source testing it.
• Sedatives — including benzodiazepines, zolpidem-type sleeping pills, opioids and alcohol: the sedation adds up.^[17]
• Blood-pressure and diabetes drugs — it mildly lowers both blood pressure and blood sugar, so monitor if you take either.
• Other prescription drugs — in lab studies it affects a liver enzyme (CYP3A4) that processes a large share of them, a route to interactions.^[18]

No dependence or withdrawal has been documented, but long-term safety data are limited.

What to do

1. Use it for stress, not as a sleeping pill. The sleep evidence is suggestive and comes mainly from stressed people.
2. Pick a standardised root extract at the studied dose — but don't treat the brand as a guarantee for your liver.
3. Skip it if you have liver, thyroid or autoimmune disease, are pregnant or breastfeeding, or take sedatives, opioids or alcohol.
4. Check with your doctor if you take blood-pressure, diabetes or other regular prescription drugs.

Further reading

• Akhgarjand C et al. Does Ashwagandha supplementation have a beneficial effect on the management of anxiety and stress? A systematic review and meta-analysis of randomized controlled trials. Phytother Res 2022.^[19]
• McIntyre D et al. Ashwagandha (Withania somnifera)-Associated Liver Injury: A Scoping Review of Clinical Characteristics and Safety Considerations. Cureus 2026.^[20]
• Philips CA et al. Ashwagandha-induced liver injury-A case series from India and literature review. Hepatol Commun 2023.^[21]
• Coope OC et al. Back to the Roots: Safety and Tolerability of Standardised Ashwagandha (Withania somnifera) Root Extract in Healthy Adults-A Systematic Review of Biomarkers and Adverse Events. Pharmaceuticals 2026.^[22]
• NIH Office of Dietary Supplements. Ashwagandha Fact Sheet for Health Professionals.^[23]