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Ingredient guide

Ashwagandha Supplements: Evidence and Safety

Ashwagandha supplements: safety cautions

Short-term tolerability findings do not establish that ashwagandha is safe for every person. Reported concerns include drowsiness, gastrointestinal symptoms, rare liver injury reports, and possible medication interactions. Pregnancy, breastfeeding, thyroid or autoimmune disorders, planned surgery, and hormone-sensitive prostate cancer require particular caution. Short studies cannot establish safety for every person, preparation, or duration of use. These reported effects do not describe every possible adverse reaction or predict an individual response. Short-term tolerability findings do not rule out rare harms or establish long-term safety. Short-term studies in other adults do not establish safety during pregnancy or breastfeeding; discuss any exposure or supplement plans with a qualified healthcare professional. Discuss these conditions and any planned surgery with your healthcare professional before considering ashwagandha; supplement research does not justify changing prescribed care. This is a condition-specific safety caution, not a treatment recommendation or an instruction to change cancer care. Discuss possible interactions with your prescriber or pharmacist before use; do not stop, replace, or adjust prescribed medicines based on supplement information.[1]

Scope and limitations

NCCIH advises avoiding ashwagandha during pregnancy and not using it while breastfeeding. Short-term studies in other adults do not establish safety during pregnancy or breastfeeding; discuss any exposure or supplement plans with a qualified healthcare professional.[1]

NCCIH does not recommend ashwagandha for people with thyroid or autoimmune disorders or those who are about to have surgery. Discuss these conditions and any planned surgery with your healthcare professional before considering ashwagandha; supplement research does not justify changing prescribed care.[1]

NCCIH advises people with hormone-sensitive prostate cancer to avoid ashwagandha because it may increase testosterone. This is a condition-specific safety caution, not a treatment recommendation or an instruction to change cancer care.[1]

Ashwagandha may interact with medicines for diabetes or high blood pressure, immunosuppressants, sedatives, anticonvulsants, and thyroid hormone medicines. Discuss possible interactions with your prescriber or pharmacist before use; do not stop, replace, or adjust prescribed medicines based on supplement information.[1]

Sources behind the starting answer

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Sources for this section

  1. Ashwagandha: Usefulness and Safety. NIH National Center for Complementary and Integrative Health. Retrieved 2026-09-30. Government health fact sheet View source →

What the stress and cortisol research reports

Ashwagandha (Withania somnifera) is a plant used in traditional Ayurvedic medicine. Randomized trials and meta-analyses have examined its effects on perceived stress and serum cortisol in adults under stress. Doses studied were about 300 mg twice daily and 240 mg per day over roughly 60 days; pooled certainty has been rated low, individual responses vary, and these findings are not a substitute for individual medical advice.[1], [2], [3], [4], [5]

Scope and limitations

Pooled certainty for stress outcomes has been rated low, and results vary between studies. In one trial of overweight, stressed adults, ashwagandha did not significantly reduce perceived stress versus placebo, although it was associated with reduced fatigue.[2], [3], [4], [5], [6]

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Sources for this section

  1. Ashwagandha: Usefulness and Safety. NIH National Center for Complementary and Integrative Health. Retrieved 2026-09-30. Government health fact sheet View source →
  2. Effects of Ashwagandha (Withania Somnifera) on stress and anxiety: A systematic review and meta-analysis.. Explore (New York, N.Y.). 2024. Systematic review and meta-analysis View source →
  3. 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 : PTR. 2022. Systematic review and meta-analysis View source →
  4. 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. Primary study View source →
  5. An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: A randomized, double-blind, placebo-controlled study.. Medicine. 2019. Randomized controlled trial View source →
  6. Exploring the efficacy and safety of a novel standardized ashwagandha (Withania somnifera) root extract (Witholytin®) in adults experiencing high stress and fatigue in a randomized, double-blind, placebo-controlled trial.. Journal of psychopharmacology (Oxford, England). 2023. Randomized controlled trial View source →

Sleep outcomes and trial limits

A meta-analysis of five randomized trials reported a small overall sleep improvement with ashwagandha. Larger subgroup effects require cautious interpretation and do not establish a universally effective regimen. The review pooled five trials with 400 adults and described the overall sleep effect as small. Larger effects appeared in subgroups with insomnia, doses of at least 600 mg per day, or treatment lasting at least eight weeks. These comparisons across trials do not establish a dose-response relationship or an individual dose recommendation; long-term safety data remain limited.[1], [2]

Scope and limitations

The review pooled five trials with 400 adults and described the overall sleep effect as small. Larger effects appeared in subgroups with insomnia, doses of at least 600 mg per day, or treatment lasting at least eight weeks. These comparisons across trials do not establish a dose-response relationship or an individual dose recommendation; long-term safety data remain limited.[1], [2]

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Sources for this section

  1. Effect of Ashwagandha (Withania somnifera) extract on sleep: A systematic review and meta-analysis.. PloS one. 2021. Systematic review and meta-analysis View source →
  2. Clinical evaluation of the pharmacological impact of ashwagandha root extract on sleep in healthy volunteers and insomnia patients: A double-blind, randomized, parallel-group, placebo-controlled study.. Journal of ethnopharmacology. 2021. Randomized controlled trial View source →

Cognition: different results in different adults

The cited trials studied different populations and preparations. A small trial in mild cognitive impairment reported favorable test results, while most cognitive tests and overall mood in a healthy-adult trial did not differ significantly from placebo over time. Based on a single small pilot trial of 50 adults with mild cognitive impairment using 300 mg twice daily for 8 weeks; the findings need confirmation in larger trials and may not apply to healthy adults. Based on one trial with 59 participants analyzed, using 225 mg per day of a liposomal root-and-leaf extract for 30 days; improvements within a treatment group do not establish superiority over placebo. The selected positive comparisons need replication and do not establish a general memory, attention, or mood benefit.[1], [2]

Scope and limitations

Based on a single small pilot trial of 50 adults with mild cognitive impairment using 300 mg twice daily for 8 weeks; the findings need confirmation in larger trials and may not apply to healthy adults.[1]

Based on one trial with 59 participants analyzed, using 225 mg per day of a liposomal root-and-leaf extract for 30 days; improvements within a treatment group do not establish superiority over placebo. The selected positive comparisons need replication and do not establish a general memory, attention, or mood benefit.[2]

Read the full evidence summary →

Sources for this section

  1. Efficacy and Safety of Ashwagandha (Withania somnifera (L.) Dunal) Root Extract in Improving Memory and Cognitive Functions.. Journal of dietary supplements. 2017. Randomized controlled trial View source →
  2. Acute and Repeated Ashwagandha Supplementation Improves Markers of Cognitive Function and Mood.. Nutrients. 2024. Randomized controlled trial View source →

Preparations, extracts and study comparison

KSM-66, Sensoril and Shoden have been studied in different clinical protocols. The useful comparison is the exact preparation, dose, population and outcome; these placebo-controlled studies do not establish that one extract is better than another. The papers describe different plant-part preparations and standardization information, including total withanolides in KSM-66 and withanolide glycosides in Shoden. A higher printed percentage or a lower extract-milligram dose does not establish superior clinical results from these trials. Their findings cannot be transferred to an unstudied powder, tea, gummy or combination product.[1], [2], [3]

Scope and limitations

The selected KSM-66, Sensoril and Shoden trials compared each studied formulation with placebo in different populations and protocols; they did not directly compare these three extracts with each other. The papers describe different plant-part preparations and standardization information, including total withanolides in KSM-66 and withanolide glycosides in Shoden. A higher printed percentage or a lower extract-milligram dose does not establish superior clinical results from these trials. Their findings cannot be transferred to an unstudied powder, tea, gummy or combination product.[1], [2], [3]

Clinical trials of ashwagandha have used a variety of preparations, and many have had small sample sizes. A finding for one studied preparation does not establish the same effect for every ashwagandha product. This summary does not rank extracts or establish that one brand is superior to another.[4]

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Sources for this section

  1. Effects of Ashwagandha ( Withania somnifera) standardized root extract on physical endurance and VO (2max) in healthy adults performing resistance training: An eight-week, prospective, randomized, double-blind, placebo-controlled study.. F1000Research. 2024. Randomized controlled trial View source →
  2. Ashwagandha and Shatavari Extracts Dose-Dependently Reduce Menopause Symptoms, Vascular Dysfunction, and Bone Resorption in Postmenopausal Women: A Randomized, Double-Blind, Placebo-Controlled Study.. Journal of menopausal medicine. 2025. Primary study View source →
  3. An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: A randomized, double-blind, placebo-controlled study.. Medicine. 2019. Randomized controlled trial View source →
  4. Ashwagandha: Usefulness and Safety. NIH National Center for Complementary and Integrative Health. Retrieved 2026-09-30. Government health fact sheet View source →

Dosage studied, timing and daily use

Human trials test particular extracts in particular populations. Once-daily and split regimens are examples of study design; the selected timing protocols do not identify the best time of day, the benefit of taking with food or a safe cycling schedule. This is the regimen from one selected trial, not evidence of the most common, recommended, maximum, or universally effective dose. It should not be transferred to another product or used as individualized dosing advice. These protocols do not identify the best time of day, prove food improves absorption, establish a cycling schedule, or determine how effects persist after discontinuation. Their 60-day and 24-week observation periods are not evidence of safety or efficacy over years.[1], [2], [3]

Scope and limitations

This is the regimen from one selected trial, not evidence of the most common, recommended, maximum, or universally effective dose. It should not be transferred to another product or used as individualized dosing advice.[1]

Doses studied were about 300 mg twice daily and 240 mg per day over roughly 60 days; pooled certainty has been rated low, individual responses vary, and these findings are not a substitute for individual medical advice.[2], [4], [5], [6]

The selected Shoden stress trial and Sensoril postmenopause trial used daily scheduled supplementation, with an after-dinner dose or morning/evening doses after meals; neither randomized participants to alternative dosing times, cycling, tapering or stopping schedules. These protocols do not identify the best time of day, prove food improves absorption, establish a cycling schedule, or determine how effects persist after discontinuation. Their 60-day and 24-week observation periods are not evidence of safety or efficacy over years.[2], [3]

Read the full evidence summary →

Sources for this section

  1. Efficacy and Safety of Ashwagandha (Withania somnifera (L.) Dunal) Root Extract in Improving Memory and Cognitive Functions.. Journal of dietary supplements. 2017. Randomized controlled trial View source →
  2. An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: A randomized, double-blind, placebo-controlled study.. Medicine. 2019. Randomized controlled trial View source →
  3. Ashwagandha and Shatavari Extracts Dose-Dependently Reduce Menopause Symptoms, Vascular Dysfunction, and Bone Resorption in Postmenopausal Women: A Randomized, Double-Blind, Placebo-Controlled Study.. Journal of menopausal medicine. 2025. Primary study View source →
  4. Effects of Ashwagandha (Withania Somnifera) on stress and anxiety: A systematic review and meta-analysis.. Explore (New York, N.Y.). 2024. Systematic review and meta-analysis View source →
  5. 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 : PTR. 2022. Systematic review and meta-analysis View source →
  6. 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. Primary study View source →

This page is educational, not individualized medical advice. A study protocol is not a personal dosing instruction. Study descriptions do not replace professional care. Ingredient research does not establish that a particular ranked product works.

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