Ashwagandha Benefits: Stress, Sleep, Dosage and Side Effects

Ashwagandha (Withania somnifera) is an Ayurvedic root whose best-studied benefits are a healthier stress response and better sleep quality: in placebo-controlled trials, adults taking 240 to 600 mg a day of root extract for 8 weeks or more reported lower stress scores, had lower cortisol and rated their sleep better.

Key Takeaways

• Ashwagandha is an evergreen shrub; supplements mostly use the root, and its main active compounds are withanolides and alkaloids (NIH Office of Dietary Supplements).
• In 64 adults with a history of chronic stress, 300 mg of root extract twice a day for 60 days lowered scores on every stress scale used and lowered serum cortisol compared with placebo (Chandrasekhar et al., 2012).
• A review of 12 trials with 1,002 people found lower stress scores than placebo, with the best results at 300 to 600 mg a day (Akhgarjand et al., 2022).
• A review of 5 trials with 400 people found a small but significant improvement in overall sleep, more noticeable at 600 mg a day or more and after 8 weeks or more (Cheah et al., 2021).
• Side effects are usually mild, but rare liver injury has been reported, and people who are pregnant, take thyroid medication or sedatives, or have liver problems should ask a clinician first.

What Is Ashwagandha?

Ashwagandha is an evergreen shrub that grows in parts of Asia, Africa and Europe. It has a long history in Ayurvedic and Unani traditions, where it is used as an adaptogen, a plant taken to help the body handle everyday stress. Most supplements use the root, and its main active compounds are withanolides and alkaloids (NIH Office of Dietary Supplements).

Our ashwagandha root extract ingredient guide covers the plant, extract quality and timing. This guide focuses on the benefits trials have measured and what the numbers mean for daily use. For how ashwagandha compares with other adaptogens and functional mushrooms, see our guides to the benefits of adaptogens and mushrooms vs adaptogens.

Ashwagandha Benefits: What Research Has Measured

Area	Who and how long	What was found
Stress scores and cortisol	64 adults with chronic stress, 300 mg root extract twice a day, 60 days	Lower scores on all stress scales and lower serum cortisol than placebo
Morning cortisol	60 healthy adults with high self-reported stress, 240 mg a day, 60 days	Larger drop in morning cortisol and DHEA-S than placebo
Stress and sleep quality	60 stressed healthy adults, 250 or 600 mg a day, 8 weeks	Lower perceived stress and cortisol at both doses; better sleep quality than placebo
Stress (review)	12 trials, 1,002 people	Lower stress scores than placebo, best at 300 to 600 mg a day
Sleep (review)	5 trials, 400 people	Small but significant improvement in overall sleep; no serious side effects reported
Strength with training	57 young men new to weight training, 300 mg twice a day, 8 weeks	Larger gains in strength and arm and chest muscle size than placebo

A Healthier Stress Response

Stress is where ashwagandha has the most research. In a double-blind trial, 64 adults with a history of chronic stress took 300 mg of a full-spectrum root extract or a placebo twice a day for 60 days. The ashwagandha group scored lower on every stress questionnaire used, and their serum cortisol, the main stress hormone, fell compared with placebo. Side effects were mild and similar in both groups (Chandrasekhar et al., 2012).

A second trial tested a lower amount. Sixty healthy adults with high self-reported stress took 240 mg of a standardized extract or a placebo once a day for 60 days. Morning cortisol and DHEA-S, another adrenal hormone, fell more on ashwagandha than on placebo. No adverse events were reported (Lopresti et al., 2019).

A 2022 review of 12 randomized trials with 1,002 participants found lower stress scores with ashwagandha than with placebo, with the dose analysis favoring 300 to 600 mg a day (Akhgarjand et al., 2022). For other ingredients studied for cortisol, see our guide to supplements to lower cortisol, and our stress, mood and nervous system guide for the daily habits that matter most.

Restful Sleep

Sleep is ashwagandha's second most studied area. In an 8-week trial, 60 stressed but healthy adults took 125 mg or 300 mg of root extract or a placebo twice a day (250 or 600 mg a day). Both doses lowered perceived stress and serum cortisol compared with placebo, and the ashwagandha groups rated their sleep quality better than the placebo group (Salve et al., 2019).

A 2021 review of 5 randomized trials with 400 participants found a small but significant improvement in overall sleep. Effects were more noticeable at 600 mg a day or more and with 8 weeks or more of use, and no serious side effects were reported (Cheah et al., 2021). Our guide to L-theanine vs ashwagandha for sleep compares the sleep trials side by side.

Strength and Training Recovery

In an 8-week trial, 57 young men with little weight training experience took 300 mg of root extract or a starch placebo twice a day while following the same resistance program. The ashwagandha group gained more bench press and leg extension strength and more arm and chest muscle size than the placebo group (Wankhede et al., 2015).

How Much Ashwagandha to Take

There is no official daily amount. Trials on stress used 240 to 1,250 mg a day of extract, and trials on sleep used 250 to 600 mg a day of root extract (NIH Office of Dietary Supplements). Most of the trials above used 240 to 600 mg a day, often split into two doses.

• Give it time. The trials measured changes after 8 weeks or about 60 days of daily use, not after a single dose.
• Extracts differ. Root extracts are made and standardized in different ways, so milligram amounts are not always comparable between products. Follow the label of the product you use.
• Morning or evening. The trials did not set a single best time. If you take it for sleep, an evening dose is common; if it is part of a morning routine, follow the product's directions.

Ashwagandha Side Effects and Who Should Ask First

Ashwagandha appears to be well tolerated in trials lasting up to about 3 months; check with a clinician before longer use. The usual side effects are mild: stomach upset, loose stools, nausea and drowsiness (NIH Office of Dietary Supplements). Ask your clinician before taking it if any of these apply:

• Liver. Rare liver injury has been reported, typically 2 to 12 weeks after starting, and most cases resolved within 1 to 4 months of stopping. People with advanced liver problems should avoid it, and anyone who develops yellowing of the skin or eyes or itching should stop and see a clinician (LiverTox, NIDDK).
• Pregnancy and breastfeeding. Some experts advise avoiding ashwagandha during pregnancy, so ask your provider first if you are pregnant, trying to conceive or breastfeeding.
• Thyroid medication. Ashwagandha may change thyroid hormone levels, so it might interact with thyroid medication.
• Sedatives and other medications. Possible interactions include sedatives, immunosuppressants, blood sugar medication and blood pressure medication.
• Hormone-sensitive conditions and surgery. Talk with your provider first if you have a hormone-sensitive condition or are preparing for surgery.

Ashwagandha vs L-Theanine

People comparing calming ingredients often weigh ashwagandha against L-theanine, the amino acid in tea. Ashwagandha is usually taken daily for weeks, and its trials measured changes in stress scores and cortisol over 8 weeks or more. L-theanine is often used for calm focus on a given day. Our guide to ashwagandha vs L-theanine for stress covers the differences, and our best supplements for stress and mood guide puts both in context. If you want L-theanine on its own, our Theanine Nasal Spray delivers it through the nose.

Where Our Forage Fits

Our Forage capsules contain 100 mg ashwagandha root extract per serving, alongside 8:1 fruiting body extracts of lion's mane, cordyceps and reishi (200 mg each) and chaga, maitake, turkey tail and shiitake (150 mg each), plus Himalayan shilajit extract (100 mg). The other ingredients are ginger extract and vegan capsules. Every ingredient is third-party tested. Each bottle holds 30 servings; follow the directions on the label.

Forage is built as a daily adaptogen blend, so ashwagandha sits beside the mushrooms rather than carrying the formula alone. Its 100 mg is less than the 240 to 600 mg a day used in most of the trials above, so the trial results are not a direct match for one serving. For the mushrooms in Forage, see our guide to adaptogenic mushrooms, and for its shilajit, our guide to how long shilajit takes to work.

Frequently Asked Questions

What are the main benefits of ashwagandha?

The best-studied benefits are a healthier stress response and better sleep quality. In placebo-controlled trials, adults taking 240 to 600 mg a day for about 8 weeks had lower stress scores and lower cortisol, and rated their sleep better.

How long does ashwagandha take to work?

The trials measured changes after about 8 weeks or 60 days of daily use, and the sleep review found larger effects at 8 weeks or more. Plan on several weeks of consistent use.

How much ashwagandha should I take a day?

There is no official amount. Most trials used 240 to 600 mg a day of root extract, often split into two doses. Follow the label of the product you use.

Does ashwagandha lower cortisol?

In several trials, serum or morning cortisol fell more on ashwagandha than on placebo after 8 weeks or 60 days, in adults with high stress at the start.

Is ashwagandha good for sleep?

A review of 5 trials found a small but significant improvement in overall sleep, more noticeable at 600 mg a day or more and after 8 weeks or more.

Is it safe to take ashwagandha every day?

It appears to be well tolerated in trials lasting up to about 3 months of daily use; check with a clinician before longer use. Rare liver injury has been reported, so stop and see a clinician if you notice yellowing of the skin or eyes or itching.

Who should not take ashwagandha?

Ask a clinician first if you are pregnant or breastfeeding, have liver problems, take thyroid medication, sedatives, immunosuppressants, blood sugar or blood pressure medication, or are preparing for surgery.

Is ashwagandha better than L-theanine?

They are used differently. Ashwagandha is taken daily for weeks and its trials measured stress scores and cortisol, while L-theanine is often used for calm focus on a given day. Some people use both.

How much ashwagandha is in Forage?

Forage contains 100 mg ashwagandha root extract per serving, along with seven mushroom fruiting body extracts and Himalayan shilajit.

Sources

• 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. Phytotherapy Research, 2022. https://pubmed.ncbi.nlm.nih.gov/36017529/
• Chandrasekhar K, Kapoor J, Anishetty S. 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 Journal of Psychological Medicine, 2012. https://pubmed.ncbi.nlm.nih.gov/23439798/
• Cheah KL, et al. Effect of Ashwagandha (Withania somnifera) extract on sleep: a systematic review and meta-analysis. PLoS One, 2021. https://pubmed.ncbi.nlm.nih.gov/34559859/
• Lopresti AL, Smith SJ, Malvi H, Kodgule R. An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: a randomized, double-blind, placebo-controlled study. Medicine (Baltimore), 2019. https://pubmed.ncbi.nlm.nih.gov/31517876/
• Salve J, Pate S, Debnath K, Langade D. Adaptogenic and anxiolytic effects of ashwagandha root extract in healthy adults: a double-blind, randomized, placebo-controlled clinical study. Cureus, 2019. https://pubmed.ncbi.nlm.nih.gov/32021735/
• Wankhede S, et al. Examining the effect of Withania somnifera supplementation on muscle strength and recovery: a randomized controlled trial. Journal of the International Society of Sports Nutrition, 2015. https://pubmed.ncbi.nlm.nih.gov/26609282/
• NIH Office of Dietary Supplements. Ashwagandha: Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/Ashwagandha-HealthProfessional/
• LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Ashwagandha. National Institute of Diabetes and Digestive and Kidney Diseases, updated 2024. https://www.ncbi.nlm.nih.gov/books/NBK548536/

These statements have not been evaluated by the Food and Drug Administration. This content is for education and is not medical advice. Our products are not intended to diagnose, treat, cure or prevent any disease. Talk with a healthcare provider before starting a new supplement if you are pregnant, breastfeeding or taking medication.