Ashwagandha (Withania somnifera) is a traditional Ayurvedic herb whose root extract is mainly studied for stress and sleep. According to the US National Center for Complementary and Integrative Health (NCCIH), some ashwagandha preparations may be effective for insomnia and stress, but evidence on anxiety is unclear and many studies are small. Trials usually used 250 to 600 mg of root extract a day for about 8 to 10 weeks. Ashwagandha may be safe for up to 3 months, but it can cause drowsiness and stomach upset, rare liver injury has been reported, and it should be avoided in pregnancy, breastfeeding, before surgery, and by people with thyroid or autoimmune disorders.
This guide brings together what the research says and links to our detailed guides on dosage, timing, side effects and choosing a product in Malaysia.
What is ashwagandha?
Ashwagandha is an evergreen shrub found in parts of India, Africa and the Middle East, and it has been used in traditional Ayurvedic medicine for thousands of years. It belongs to the same plant family as tomatoes and chillies (the nightshade family). Supplements usually contain extracts of the root, the leaf, or both.
The plant contains a group of compounds called withanolides. Many labels list the percentage of withanolides, or a branded extract name such as KSM-66®, so you can compare products. See our guide to KSM-66 vs other ashwagandha extracts.
Ashwagandha is often called an "adaptogen", meaning a herb said to help the body cope with stress. This is a traditional and marketing term, not a medical classification.
What does research say about ashwagandha's benefits?
Many clinical trials have studied ashwagandha, but according to the NCCIH, many had small numbers of people and used different preparations. Here is what the main evidence says:
| Use | What the evidence says |
|---|---|
| Sleep | A 2021 review of 5 trials (400 adults) by researchers at Universiti Sains Malaysia found a small but significant improvement in overall sleep. The effect was clearer in adults with insomnia, at doses of 600 mg a day or more, and with treatment for 8 weeks or longer. |
| Stress | A 2022 review of 12 trials (1,002 adults) found ashwagandha reduced stress scores compared with placebo, but the certainty of the evidence was low. The NCCIH says some preparations may be effective for stress. |
| Anxiety | The same 2022 review found lower anxiety scores, but the NCCIH describes the evidence on anxiety as unclear. |
| Male fertility and testosterone | Limited evidence suggests taking it for 2 to 4 months may increase testosterone levels and sperm quality. |
| Other uses | According to the NCCIH, there is not enough evidence for asthma, athletic performance, memory and thinking, diabetes, menopause or female infertility. |
Ashwagandha is not a treatment for anxiety disorders, depression or insomnia. If stress or poor sleep is affecting your daily life, see a doctor. For more detail, read our guide to ashwagandha for stress and sleep and our guide to insomnia (susah tidur).
How much ashwagandha do studies use?
There is no official recommended dose. Doses vary between products, so follow the label of the product you use. In the clinical trials:
| Study | Daily dose of root extract | Length |
|---|---|---|
| Stress, 64 adults (2012) | 600 mg (300 mg twice a day) | 60 days |
| Stress, 60 adults (2019) | 250 mg or 600 mg (split into two doses) | 8 weeks |
| Insomnia and anxiety, 60 adults (2019) | 600 mg (300 mg twice a day, with milk or water) | 10 weeks |
The 2022 review found the benefit for stress at doses of 300 to 600 mg a day. Taking more than the label says has not been shown to work better. For timing, food and a simple routine, see our guide to how to take ashwagandha.
How long does ashwagandha take to work?
Ashwagandha is not a quick fix. Most trials lasted 8 to 10 weeks, and the Universiti Sains Malaysia review found the effect on sleep was clearer with treatment of 8 weeks or longer. According to the NCCIH, it may be safe for up to 3 months, but there is not enough information on long-term use. Read more in how long ashwagandha takes to work.
What are the side effects of ashwagandha?
According to the NCCIH, ashwagandha may cause:
- drowsiness;
- stomach upset;
- diarrhoea;
- vomiting.
Liver injury is rare but serious. In a case series from Iceland and the US, people developed jaundice (yellow skin or eyes), nausea, tiredness, itching and abdominal discomfort 2 to 12 weeks after starting ashwagandha; their liver tests returned to normal within 1 to 5 months after stopping. In a case series from India, three people who already had chronic liver disease developed liver failure and died.
Stop taking ashwagandha and see a doctor if your skin or eyes turn yellow, or you have severe itching, nausea or abdominal pain. If you feel drowsy, do not drive until you know how it affects you. See our guide to ashwagandha side effects.
Who should not take ashwagandha?
According to the NCCIH, ashwagandha should be avoided or is not recommended if you:
- are pregnant or breastfeeding (see ashwagandha in pregnancy and breastfeeding);
- are about to have surgery;
- have an autoimmune disorder or a thyroid disorder (see our guide to thyroid problems);
- have hormone-sensitive prostate cancer.
Ashwagandha may also interact with medicines for diabetes and high blood pressure, immunosuppressants, sedatives, anti-seizure medicines and thyroid hormone. Because of the liver cases above, people with liver disease should also ask a doctor first. Read who should not take ashwagandha and ashwagandha and medications.
How to choose ashwagandha in Malaysia
- Check the extract. Look for the plant part (root, leaf or both), the extract name and the withanolide percentage, so you can compare like with like.
- Check halal status. Look for halal certification from JAKIM or from one of the foreign halal certification bodies JAKIM recognises (88 bodies in 49 countries as of October 2024). Check whether the capsule shell is gelatin or plant-based.
- Buy from the brand or an authorised seller, and check the batch number and expiry date.
- Use one ashwagandha product at a time, so you do not take a double dose from two products.
For a full checklist, see our guide to how to choose an ashwagandha supplement in Malaysia.
All our ashwagandha guides
- How to choose an ashwagandha supplement in Malaysia
- KSM-66 vs other ashwagandha extracts
- How to take ashwagandha: morning or night, with food, and how much
- How long does ashwagandha take to work?
- Ashwagandha for stress and sleep
- Ashwagandha side effects
- Who should not take ashwagandha
- Ashwagandha and medications
- Ashwagandha in pregnancy and breastfeeding
Frequently asked questions (FAQ)
What is ashwagandha good for?
Ashwagandha is mainly studied for stress and sleep. According to the US National Center for Complementary and Integrative Health (NCCIH), research shows some ashwagandha preparations may be effective for insomnia and stress, but evidence on anxiety is unclear and there is not enough evidence for most other uses, such as athletic performance, diabetes or menopause.
Is ashwagandha safe?
According to the NCCIH, ashwagandha may be safe when taken for up to 3 months, but its long-term safety is unknown. It can cause drowsiness, stomach upset, diarrhoea and vomiting, and rare cases of liver injury have been reported. It should be avoided in pregnancy and breastfeeding.
How much ashwagandha should I take per day?
Follow the label of your product. In clinical trials, adults usually took 250 to 600 mg a day of root extract, often split into two doses, for about 8 to 10 weeks. Taking more than the label says has not been shown to work better.
How long does ashwagandha take to work?
Most studies lasted about 8 to 10 weeks. A 2021 review by researchers at Universiti Sains Malaysia found that the effect on sleep was more noticeable with treatment lasting 8 weeks or longer.
Who should not take ashwagandha?
The NCCIH advises avoiding ashwagandha during pregnancy and breastfeeding, before surgery, and if you have an autoimmune or thyroid disorder or hormone-sensitive prostate cancer. Ask a doctor or pharmacist first if you take medicines for diabetes, high blood pressure, thyroid, seizures, sleep or the immune system, or if you have liver disease.
Can ashwagandha damage the liver?
Rarely, yes. Published case reports describe liver injury, usually with jaundice and itching, appearing 2 to 12 weeks after starting ashwagandha. Most people recovered after stopping, but in an Indian case series, three people with existing chronic liver disease developed liver failure and died. Stop and see a doctor if your skin or eyes turn yellow.
Is ashwagandha halal?
Ashwagandha is a plant, but a capsule may contain other ingredients, including gelatin shells. Look for halal certification from JAKIM or a foreign halal body recognised by JAKIM, and check what the capsule is made of.
Drann Ashwagandha KSM-66®
- KSM-66® ashwagandha root extract
- Supports a calm mood and sleep quality as part of a healthy routine
- Made from halal ingredients
- Label use: 1 to 2 capsules a day, about 2 hours before bedtime
Not suitable during pregnancy or breastfeeding. Talk to your doctor or pharmacist first if you take regular medicines or have a thyroid, autoimmune or liver condition.
Disclaimer
This article is for general information only and is not a substitute for advice from a doctor or pharmacist. Health supplements are not intended to diagnose, treat, cure or prevent any disease.
References
- Ashwagandha — National Center for Complementary and Integrative Health (NCCIH), US National Institutes of Health
- Cheah KL, et al. Effect of ashwagandha (Withania somnifera) extract on sleep: a systematic review and meta-analysis. PLoS One. 2021;16(9):e0257843
- 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;36(11):4115-4124
- Chandrasekhar K, et al. 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 J Psychol Med. 2012;34(3):255-62
- Salve J, et al. Adaptogenic and anxiolytic effects of ashwagandha root extract in healthy adults: a double-blind, randomized, placebo-controlled clinical study. Cureus. 2019;11(12):e6466
- Langade D, et al. Efficacy and safety of ashwagandha (Withania somnifera) root extract in insomnia and anxiety: a double-blind, randomized, placebo-controlled study. Cureus. 2019;11(9):e5797
- Björnsson HK, et al. Ashwagandha-induced liver injury: a case series from Iceland and the US Drug-Induced Liver Injury Network. Liver Int. 2020;40(4):825-829
- Philips CA, et al. Ashwagandha-induced liver injury: a case series from India and literature review. Hepatol Commun. 2023;7(10)
- JAKIM recognises five additional foreign halal certification bodies (18 October 2024) — Bernama
