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Ashwagandha for Stress: Dose, Form, and Safety

Ashwagandha for stress has fair but imperfect evidence. In small trials lasting about 8 weeks, root extract at 240 to 600 mg a day lowered stress and anxiety scores more than placebo (grade B), though results varied widely and one 2025 review found no clear effect on perceived stress. Rare liver injury and thyroid overactivity have been reported. NIH advises against it in pregnancy and with thyroid or autoimmune disorders.

Published How we grade evidenceEditorial policy

The short version

  • Stress: most reviews found lower stress scores than with placebo; one 2025 review did not. Grade B (Arumugam 2024; Albalawi 2025).
  • Anxiety: scores fell more than with placebo, mostly in small trials that disagreed a lot. Grade B (Marchi 2025; Fatima 2024).
  • Cortisol (a stress hormone): lower in pooled trials. Grade B (Fornalik 2026).
  • Sleep: a small improvement, larger in insomnia. Grade B (Cheah 2021).
  • Dose: most trials gave adults 240 to 600 mg of extract a day for about 8 weeks (Lopresti 2019; Marchi 2025).
  • Safety: rare but serious liver injury, and thyroid hormone changes (Björnsson 2020; Sharma 2018).

Ashwagandha (Withania somnifera) is an evergreen shrub used in Ayurvedic medicine. Supplements contain extracts of the root, the leaf, or both, and its active compounds include withanolides (NCCIH).

Does ashwagandha lower stress?

Grade B. A 2024 meta-analysis pooled 9 randomized trials with 558 people. Perceived Stress Scale scores ended 4.72 points lower than with placebo, and clinician-rated Hamilton Anxiety Scale scores fell too (Arumugam 2024). An earlier review of 12 trials with 1,002 adults aged 25 to 48 also found less stress, but rated the certainty of the evidence low (Akhgarjand 2022).

Not every result agrees. A 2025 meta-analysis of six perceived-stress trials found no significant difference from placebo, though cortisol fell (Albalawi 2025). In a 12-week trial of overweight adults aged 40 to 75 taking 200 mg twice a day, stress dropped, but no more than with placebo (Smith 2023). Our database page also grades ashwagandha B for stress.

Does ashwagandha help anxiety?

Grade B. A 2025 review of people with mental disorders pooled 14 trials (360 people on ashwagandha, 353 controls), mostly in anxiety disorders. Anxiety improved more than in control groups, the result held after outlier trials were removed, and side effects were no more common (Marchi 2025). A 2024 review of 5 trials (254 people with anxiety, insomnia or both) found Hamilton anxiety scores 5.96 points lower than with placebo, but the five results differed sharply, and the authors called for bigger trials (Fatima 2024). NCCIH, writing in 2023, still called the anxiety evidence unclear (NCCIH).

Grade C for generalized anxiety disorder (GAD). In 40 people with GAD already on SSRI antidepressants, adding 1 g a day of root extract for 6 weeks lowered Hamilton scores by 14 points, against 8 with placebo (Fuladi 2021). In an older trial of 39 people with anxiety disorders, 88.2% responded to an ethanol extract by week 6, against 50% on placebo (Andrade 2000). Our GAD page also rates it C.

Does ashwagandha lower cortisol?

Grade B. A 2026 meta-analysis of 23 placebo-controlled trials with 1,706 people found lower cortisol with ashwagandha (Fornalik 2026). A 2025 review of seven trials found it 1.16 µg/dL lower, yet how stressed people felt did not change significantly (Albalawi 2025). A lower lab number doesn't prove you'll feel calmer. Our database page grades cortisol C, from one trial; we grade it B because three reviews pool several trials (Arumugam 2024).

Does ashwagandha help sleep?

Grade B. Sleep was a secondary outcome. A 2021 meta-analysis of 5 trials with 400 adults found a small improvement in overall sleep. The effect was larger in people diagnosed with insomnia, at 600 mg a day or more, and after 8 weeks or longer (Cheah 2021). That matches the B our database gives ashwagandha for insomnia.

What dose and form did the trials use?

Grade C for choosing one dose over another. Only two small trials compared doses head to head, and both found benefit at the lowest dose tested, 250 and 125 mg a day (Salve 2019; Pandit 2024). The doses tested:

  • 240 mg of standardized extract once a day for 60 days (60 adults): anxiety scores and morning cortisol fell more than with placebo; a combined stress, anxiety and depression scale only neared significance (Lopresti 2019).
  • 300 mg of root extract twice a day for 60 days (64 adults with chronic stress): lower scores on every stress scale, and lower cortisol (Chandrasekhar 2012).
  • 250 or 600 mg a day for 8 weeks (60 adults): both doses lowered stress scores and cortisol, with stronger statistics at 600 mg (Salve 2019).
  • A root-and-leaf water extract at 125, 250 or 500 mg a day for 8 weeks (98 adults analyzed) lowered stress at all three doses (Pandit 2024).

Across the 13 oral trials in the 2025 review, the median dose was 600 mg a day (Marchi 2025), and a dose-response analysis linked the stress benefit to 300 to 600 mg a day (Akhgarjand 2022).

Form. Most trials above used a root extract. Few abstracts report the withanolide content. One trial used 500 mg standardized to 2.5% withanolides (12.5 mg a day) plus piperine, and three of its authors worked for the extract maker (Majeed 2023). A 2026 review saw hints that effects vary with withanolide content (Fornalik 2026).

Reading a label. Find the amount of extract per day and compare it with the trial doses, mostly 240 to 600 mg. A blend total can't be compared.

How long does ashwagandha take to work?

Most trials judged results at about 8 weeks, often 60 days (Marchi 2025; Lopresti 2019). In one small trial, anxiety trended lower at week 2 and differed significantly from placebo at week 6 ( Grade C, Andrade 2000). A fair test is about 8 weeks at a steady dose.

NCCIH says ashwagandha may be safe for up to 3 months, and long-term safety is unknown (NCCIH). A 12-month study of 191 adults, with no placebo group, reported 18 mild side effects and no meaningful change in liver enzymes (Salve 2026).

How much should you trust these trials?

  • Small and varied: NCCIH notes that many trials were small and used different preparations (NCCIH), and most ran about 8 weeks.
  • Inconsistent: results varied hugely between trials (I², a measure of disagreement, was 93.8% and 98% in two reviews) (Akhgarjand 2022; Fatima 2024). The newest review, of 22 trials, calls for better trials to settle dose and duration (Alsanie 2026).
  • Industry ties: some trial authors worked for the extract maker (Majeed 2023), and authors of a 2026 safety review had worked for supplement companies (Coope 2026).
  • Publication bias: one 2025 review looked for missing negative studies and found none (Albalawi 2025).

What we'd skip

  • Ashwagandha in place of care for an anxiety disorder. In the GAD trial it was added to SSRIs, not swapped for them (Fuladi 2021).
  • Leaf-only products, or labels that don't name the plant part. Trials used root or root-and-leaf extracts, and the Netherlands plans to ban the leaf (see below).
  • Blends that hide the ashwagandha dose. They can't be compared with the trials, and four of five people in one liver-injury series also took other supplements (Björnsson 2020).

Safety and interactions

Common side effects. NCCIH lists drowsiness, stomach upset, diarrhea and vomiting (NCCIH). In a 2026 review of 23 trials (2,317 healthy adults), mild stomach discomfort, headache and drowsiness were uncommon and also seen in comparison groups (Coope 2026). In the largest trial, 1,002 adults took 600 mg a day or placebo for 8 weeks. Side-effect reports came to 28 (5.6%) on ashwagandha and 46 (9.2%) on placebo, none serious, and liver tests did not change (Pakhale 2026).

Liver injury: rare, but can be serious. Björnsson 2020 described five people in Iceland and the US who became jaundiced (yellow skin and eyes), with nausea, tiredness, itching and belly discomfort, after a delay of 2 to 12 weeks. The injury mainly slowed bile flow, nobody had liver failure, and liver tests normalized within 1 to 5 months in the four who were followed up (Björnsson 2020). In an Indian series of 8 people who took ashwagandha alone, 5 already had chronic liver disease, and 3 of them developed liver failure and died (Philips 2023). A 2026 review of 25 published cases found most recovered after stopping, with one liver transplant and three deaths in people with cirrhosis (McIntyre 2026). Skip it if you have liver disease.

Thyroid. In 50 adults with subclinical hypothyroidism (a mildly underactive thyroid), 600 mg a day of root extract for 8 weeks shifted TSH, T3 and T4 compared with placebo, which the authors call normalizing (Sharma 2018). Across trials, T4 rose 0.61 µg/dL on average (Fornalik 2026). Case reports describe thyrotoxicosis (an overactive thyroid) in a 32-year-old woman (van der Hooft 2005), a 73-year-old woman with a racing heart after two years of use (Kamal 2022), and a 47-year-old man two months after starting it (Hayashi 2024).

Pregnancy and breastfeeding. NCCIH says to avoid ashwagandha in pregnancy and not to use it while breastfeeding (NCCIH). If you are pregnant, breastfeeding or under 18, ask a clinician.

Medicines and conditions. NCCIH says ashwagandha might interact with diabetes and blood-pressure medicines, immunosuppressants, sedatives, anti-seizure drugs and thyroid hormone, and advises against it before surgery or with autoimmune or thyroid disorders (NCCIH). No clinical interaction studies were found; the cautions rest on these findings:

  • Blood sugar: fasting glucose fell 3.09 mg/dL on average across 11 trials, with very low certainty (Farrin 2026).
  • Sedatives: drowsiness is a known side effect, and France's food safety agency advises people on sedatives not to take ashwagandha supplements (ANSES opinion, 19 April 2024).
  • Immune system: a 2025 review of lab, animal and human studies placed ashwagandha among 15 herbs with the most evidence of stimulating immunity, which may flare autoimmune skin disease (Weiner 2025).
  • Antidepressants: adverse-event reports describe severe diarrhea with sertraline, and vomiting with escitalopram, alongside ashwagandha (Siwek 2023).
  • Hormones: testosterone rose in men in pooled trials (Fornalik 2026); NCCIH says people with hormone-sensitive prostate cancer should avoid ashwagandha.

Upper limit. We found none; Denmark's food agency said in March 2026 that an acceptable daily intake can't be set (Fødevarestyrelsen, 11 March 2026).

Rules in other countries (official pages, checked 7 November 2026):

  • Denmark: ashwagandha products are illegal to sell as food, supplements included. The food agency cites a Technical University of Denmark risk assessment that found harm to sex hormones and reproduction, and possible effects on metabolism, immunity and the nervous system (Fødevarestyrelsen).
  • Netherlands: after a 2025 consultation, the health ministry said its planned rules will ban the leaf in herbal products and allow the root only with a warning against use in pregnancy, breastfeeding or liver or thyroid problems, pending a new risk assessment. It and Germany asked the European Commission for an EU safety review (consultation report). We could not confirm a start date.
  • France: the food safety agency advises people with thyroid, liver or heart disease, pregnant women and people on sedatives not to take ashwagandha supplements (ANSES).

When to see a doctor

  • Stop it and see a doctor quickly for yellowing of the skin or eyes, itching, nausea, unusual tiredness or belly pain, the signs of liver injury in the case reports (Björnsson 2020).
  • See a doctor for a racing heart, weight loss, fevers at night or diarrhea after starting it, signs of an overactive thyroid in case reports (Kamal 2022; Hayashi 2024).
  • Ask before starting if you have liver disease, a thyroid or autoimmune condition, or planned surgery, or take medicines for thyroid, diabetes, blood pressure, seizures, sleep or anxiety, or immune-suppressing drugs. Don't stop a prescribed medicine on your own; ask the prescriber or pharmacist.
  • Book a visit if stress or anxiety lasts for weeks and disrupts work, sleep or relationships, or you have panic attacks.
  • If you have thoughts of harming yourself, in the US call or text 988; elsewhere, call your local emergency number.
  • If you are pregnant, breastfeeding or under 18, ask a clinician.

FAQ

How much ashwagandha should I take for stress? Most adult trials used 240 to 600 mg of extract a day, often in two doses. Compare the extract amount on your label with those doses.

Is ashwagandha safe to take every day? In trials of a few months, side effects were mild and about as common as with placebo. Rare liver and thyroid harms are reported, and long-term safety is unknown.

Why is ashwagandha banned in Denmark? Its food agency says ashwagandha products are illegal to sell as food there, citing harm to sex hormones and reproduction (checked 7 November 2026).

What is the best form of ashwagandha for stress? A root extract that states its daily extract amount matches what most trials used (grade B for stress). Leaf-only products and blends that hide the dose don't.

Can I take ashwagandha with antidepressants or thyroid medicine? Ask your prescriber or pharmacist first. NIH lists thyroid hormone and sedatives as possible interactions, and reports describe side effects with SSRIs.

Sources

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