Ashwagandha

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By Nikola · Precision Nutrition L1 · Updated 5 November 2026

Ashwagandha (Withania somnifera, also called Indian ginseng) is an evergreen shrub whose root, and sometimes leaf, is sold as a supplement for stress and sleep. It has been used for thousands of years, above all in traditional Ayurvedic medicine. Small, short trials, most of them in India, suggest that root extracts may lower perceived stress and improve sleep a little, with doses of roughly 250 to 600 mg of extract a day for 6 to 12 weeks. It seems safe for most people for up to about 3 months; long-term safety is unknown. Rare cases of liver injury and effects on thyroid hormones have been reported, it should be avoided in pregnancy, and Denmark banned it in food supplements in 2023.

What the research says

The main active compounds are withanolides. Studies use many different extracts, which makes them hard to compare.

• Stress: weak to moderate. A 2021 systematic review of 7 studies with 491 adults in India, lasting 6 to 8 weeks, found less stress, anxiety, sleeplessness and fatigue and lower cortisol than placebo, with doses of 240 to 1,250 mg of extract a day; several studies showed more benefit at 500 to 600 mg. Not every trial agrees: in 120 overweight adults taking 200 mg twice a day for 12 weeks, perceived stress did not fall compared with placebo, though fatigue improved.
• Anxiety: weak. NCCIH calls the evidence unclear. An international psychiatry taskforce (WFSBP/CANMAT, 2022) gave only a provisional recommendation of 300 to 600 mg of root extract standardised to 5% withanolides for generalised anxiety disorder, saying more research is needed.
• Sleep: weak to moderate. A 2021 meta-analysis of 5 studies with 372 adults found a small but significant improvement in sleep. Effects were larger at 600 mg a day, with at least 8 weeks of use, and in people with insomnia. In one trial of 150 adults with insomnia symptoms, sleep quality improved in 72% on ashwagandha against 29% on placebo.
• Testosterone and sperm quality: weak. Limited evidence suggests 2 to 4 months of use may raise testosterone and improve sperm quality.
• Not shown. Evidence is insufficient for athletic performance, memory and thinking, diabetes, menopause, female infertility, asthma and COVID-19.

There is no EU-authorised health claim for ashwagandha in Regulation (EU) 432/2012. A label saying it “reduces stress” is not an approved claim.

Dose and forms

• Doses in trials. Mostly 250 to 600 mg a day of root extract, or 120 mg a day of one root and leaf extract, for 6 to 12 weeks. The larger sleep effects came at 600 mg a day.
• Forms. Most products use root extract; some combine root and leaf. Extracts are often standardised to a percentage of withanolides, for example 5%.
• Duration. Safety data cover up to about 3 months. Beyond that, nobody knows.
• Time of day. The sources used here give no best time. Drowsiness is a reported side effect, so see how it affects you before you drive.

Food sources

Ashwagandha is a medicinal plant, not an everyday food. Supplements contain the root, the leaf or an extract of root and leaf. If you are curious about other plants used in Ayurvedic cooking, our entries on turmeric, ginger, cardamom, fenugreek, cinnamon and ghee cover them as foods, with nutrition data. For a warm drink from the same kitchen, see our golden milk recipe.

Side effects and interactions

• Common. Drowsiness, stomach upset, loose stools or diarrhoea, nausea and sometimes vomiting.
• Liver. Liver injury is rare, but a number of cases have been linked to ashwagandha supplements. In five published cases, people aged 21 to 62 had taken 450 to 1,350 mg a day for 1 week to 4 months; most recovered after stopping. Product contents were not always checked.
• Thyroid. Ashwagandha can raise thyroid hormones. In a trial in 50 people with subclinical hypothyroidism, 300 mg twice a day for 8 weeks lowered TSH and raised T3 and T4. Three case reports describe thyrotoxicosis (too much thyroid hormone) in women aged 32 to 73, which settled after they stopped.
• Medicines. It may interact with thyroid hormone, medicines for diabetes and high blood pressure, immunosuppressants, sedatives and anticonvulsants. Talk to your doctor before combining.

Who should avoid it

• Pregnancy and breastfeeding. NCCIH says to avoid it in pregnancy and not to use it while breastfeeding. Some experts cite reports of possible miscarriage; the American Herbal Pharmacopoeia disputes this, but the safe choice is to avoid it.
• Thyroid or autoimmune conditions. NCCIH does not recommend it for people with thyroid disorders or autoimmune disorders.
• Hormone-sensitive prostate cancer. Avoid, since it may raise testosterone.
• Before surgery. Not recommended for people about to have an operation.
• Liver or heart problems, under-18s, people on sedatives. France’s food safety agency ANSES advised against use in these groups in 2024, as well as in pregnancy, breastfeeding and endocrine disorders.

Rules differ across Europe. Denmark banned ashwagandha in food supplements in 2023, after a 2020 risk assessment from the Technical University of Denmark found too little evidence to set a safe intake. The Netherlands’ public health institute advised against its use in 2024, and the UK Food Standards Agency opened a call for evidence the same year. As of July 2026, EU regulators were considering a formal review that could lead to EU-wide restrictions. Check the rules where you live.

How to choose a good product

• Plant part. The label should say root, leaf or both. India’s Ministry of Ayush advised in 2021 against using the leaves in any form, and most trials used root extract.
• Amount and standardisation. Look for milligrams of extract per capsule and the withanolide percentage, so you can compare with trial doses.
• Single ingredient. A product with ashwagandha alone makes it easier to spot side effects.
• Independent testing. Seals from ConsumerLab.com, NSF International or US Pharmacopeia show that a product contains what the label says and no harmful levels of contaminants. They do not guarantee that it is safe or effective.

We do not recommend specific products on this page. If you want to try ashwagandha, tell your doctor, especially if you take any regular medicine.

FAQ

What is ashwagandha good for?

Small trials suggest root extracts may reduce perceived stress and slightly improve sleep, especially in people with insomnia, over 6 to 12 weeks. The evidence is limited, and there is no authorised health claim for it in the EU.

Is ashwagandha safe to take every day?

For most healthy adults it seems safe for up to about 3 months; there are no data on longer use. Rare liver injury and thyroid effects have been reported, and it should be avoided in pregnancy, while breastfeeding and with thyroid disease. See also our article Is ashwagandha safe to take daily?

Why is ashwagandha banned in Denmark?

A 2020 risk assessment for the Danish food authority found too little evidence to establish a safe intake, with concerns about miscarriage, thyroid and sex hormones. Denmark banned it in food supplements in 2023.

Related entries and articles

• Turmeric and ginger
• Ghee and cardamom
• Other supplements: melatonin, magnesium, probiotics
• Is ashwagandha safe to take daily?
• Why sleep is the cornerstone of a healthy lifestyle
• Ayurvedic diet for beginners

Sources

1. NCCIH: Ashwagandha. nccih.nih.gov
2. NIH Office of Dietary Supplements: Ashwagandha, Fact Sheet for Health Professionals, updated 2 May 2025. ods.od.nih.gov
3. Commission Regulation (EU) No 432/2012 – permitted health claims (no entry for ashwagandha). legislation.gov.uk
4. Hancocks N. Timeline: Will authorities de-throne the King of Herbs? NutraIngredients, 6 July 2026. nutraingredients.com
5. French agency warns ashwagandha unsafe in specific populations. NutraIngredients, 17 June 2024. nutraingredients.com
6. NIH Office of Dietary Supplements: Dietary Supplements: What You Need to Know, updated 4 January 2023. ods.od.nih.gov

This page is for information only and is not medical or dietary advice.