{"@context":"https://schema.org","@type":"DietarySupplement","id":"https://nutripedia.co.uk/items/ashwagandha","url":"https://nutripedia.co.uk/items/ashwagandha","name":"Ashwagandha","category":"Wellness","tagline":"Adaptogenic herb for stress reduction and hormonal balance.","verdict":"promising","evidenceRating":3,"verdictSummary":"Promising evidence for stress and cortisol reduction. Some support for testosterone in men and exercise performance. Long-term safety data is limited.","dosage":{"recommended":"300–600","unit":"mg (root extract)","timing":"Morning or evening","notes":"KSM-66 and Sensoril are the most studied extracts. Effects may take 4–8 weeks."},"keyBenefits":["Reduces perceived stress and cortisol levels","May support healthy testosterone levels in men","Could improve sleep quality","Potential exercise performance benefits"],"warnings":["May interact with thyroid medications","Not recommended during pregnancy","Rare reports of liver injury at high doses — use standardised extracts","Long-term safety data beyond 3 months is limited"],"evidenceSummary":null,"dosing":null,"safety":null,"whoMightBenefit":[],"whoShouldAvoid":[],"regulatoryNotes":null,"faqs":[{"question":"What does the research say about ashwagandha and stress?","answer":"A systematic review of 12 RCTs found significant reductions in validated stress scores (e.g., Perceived Stress Scale) and serum cortisol levels with standardised ashwagandha root extract. One 60-day RCT (n=64, PMID: 23439798) found KSM-66 at 300 mg twice daily reduced PSS scores by 44% versus 5.5% in the placebo group, and reduced serum cortisol by 27.9% versus 7.9%. Effects are typically observed from 4 weeks of continuous use."},{"question":"What dosage ranges have been studied for ashwagandha?","answer":"Published trials have used a range of 120 mg/day (Sensoril extract) to 1,250 mg/day of root powder. The most extensively studied doses for stress and performance outcomes are 300 mg twice daily or 600 mg once daily of KSM-66 standardised root extract (5% withanolides). A 2019 meta-analysis (n=1,002) identified a dose-response relationship for cortisol reduction with higher doses showing greater effect. Most trials ran for 8–12 weeks; effects beyond 3 months have not been studied in large RCTs."},{"question":"What side effects have been reported in trials of ashwagandha?","answer":"Short-term trials (8–12 weeks) at doses of 300–600 mg/day generally report side effect profiles comparable to placebo. The most commonly reported adverse events are mild GI effects (nausea, loose stools). The European Food Safety Authority and the UK's FSA have published safety assessments noting that rare cases of drug-induced liver injury (DILI) have been reported in association with ashwagandha products — a 2023 systematic review identified 7 cases, most resolving on discontinuation. The FSA concluded that standardised extracts at recommended doses are unlikely to pose a significant hepatotoxicity risk in healthy adults."},{"question":"Is there evidence for ashwagandha during pregnancy or with thyroid medications?","answer":"Animal studies suggest ashwagandha may have uterotonic properties; no safety data in human pregnancy exists from RCTs, and it is generally excluded from trial populations. Regarding thyroid interactions, one 8-week RCT (n=50) in adults with subclinical hypothyroidism found ashwagandha root extract 600 mg/day significantly increased T3 and T4 levels versus placebo. The literature therefore cautions that ashwagandha may potentiate thyroid hormone effects — individuals taking levothyroxine or other thyroid medications are advised to consult a prescriber before use."},{"question":"What forms of ashwagandha have the strongest evidence base?","answer":"KSM-66 (Ixoreal Biomed) is a full-spectrum root extract standardised to ≥5% withanolides and has the largest body of RCT evidence for stress, testosterone, and sleep outcomes. Sensoril (Natreon Inc.) is a root-and-leaf extract standardised to ≥10% withanolides at lower doses (120–250 mg/day) and has evidence for stress and cognitive outcomes. Non-standardised ashwagandha root powder typically contains 0.5–1% withanolides, is less well studied in RCTs, and makes dose-to-outcome comparisons unreliable. Most published trials specify the extract used."},{"question":"What does the research say about ashwagandha and sleep quality?","answer":"A 2021 meta-analysis of 5 RCTs (n=400, PMID: 34710195) found that ashwagandha extract significantly improved overall sleep quality (SMD −0.79) and reduced sleep onset latency compared with placebo. Subgroup analyses found the benefit was more pronounced in participants with diagnosed insomnia disorder (SMD −1.22) than in the general population. Proposed mechanisms include cortisol reduction, GABA-mimetic withanolide activity, and triethylene glycol-mediated sleep induction."},{"question":"What does the research say about ashwagandha and testosterone?","answer":"A meta-analysis of 5 RCTs (n=236) found ashwagandha supplementation significantly increased serum testosterone in men (SMD +0.54, 95% CI 0.09–0.99). Studies primarily enrolled men with subfertility or those undergoing resistance training; extrapolation to the general male population requires caution. Proposed mechanisms include HPA-axis modulation reducing cortisol (which suppresses gonadotropins) and direct stimulation of luteinising hormone. One 90-day trial in men with oligospermia (PMID: 23796876) found a 14.7% increase in serum testosterone alongside improved sperm parameters."}],"research":{"totalCount":17,"papers":[{"title":"Effects of ashwagandha (Withania somnifera) on mental health in adults: A systematic review and dose-response meta-analysis of randomized controlled trials","year":2026,"journal":"Complementary Therapies in Medicine","doi":"10.1016/j.ctim.2026.103325","pmid":"","url":"https://doi.org/10.1016/j.ctim.2026.103325","studyDesign":"meta-analysis","fields":[],"conclusion":"Dose-response meta-analysis of 22 RCTs (1,391 participants) demonstrated ashwagandha significantly alleviates stress, anxiety, and depression. Lower doses (≤500 mg/day) combined with longer treatment periods (>8 weeks) showed superior outcomes. Supports ashwagandha as a clinically relevant adaptogen pending further high-quality trials.","abstract":"","citationCount":0},{"title":"Effects of Ashwagandha Supplements on Cortisol, Stress, and Anxiety Levels in Adults: A Systematic Review and Meta-Analysis","year":2025,"journal":"BJPsych Open","doi":"10.1192/bjo.2025.10136","pmid":"","url":"https://doi.org/10.1192/bjo.2025.10136","studyDesign":"meta-analysis","fields":[],"conclusion":"Meta-analysis of 15 RCTs (873 participants) found ashwagandha produced statistically significant reductions in serum cortisol, Perceived Stress Scale scores, and HAM-A scores vs placebo. No significant improvement in quality of life was observed. Concluded safe and effective for stress and anxiety reduction in adults.","abstract":"","citationCount":0},{"title":"The effect of Withania somnifera (Ashwagandha) on mental health symptoms in individuals with mental disorders: systematic review and meta-analysis","year":2025,"journal":"BJPsych Open","doi":"10.1192/bjo.2025.10885","pmid":"41140145","url":"https://doi.org/10.1192/bjo.2025.10885","studyDesign":"meta-analysis","fields":[],"conclusion":"Systematic review and meta-analysis of 14 RCTs (360 treatment, 353 controls) found evidence supporting ashwagandha efficacy for anxiety symptoms in individuals with mental disorders. Promising signals for depression and insomnia. Median effective dose was 600 mg/day over 8 weeks, with good tolerability. Larger trials needed.","abstract":"","citationCount":0},{"title":"Effects of Ashwagandha (Withania Somnifera) on stress and anxiety: A systematic review and meta-analysis","year":2024,"journal":"Explore (NY)","doi":"10.1016/j.explore.2024.103062","pmid":"39348746","url":"https://doi.org/10.1016/j.explore.2024.103062","studyDesign":"meta-analysis","fields":[],"conclusion":"Analysis of 9 RCTs (558 patients) found ashwagandha formulations produced statistically significant reductions in perceived stress, anxiety scale scores, and serum cortisol levels vs placebo. Adverse effects were mostly mild. Supports ashwagandha as an effective and tolerable adaptogen for stress and anxiety management in adults.","abstract":"","citationCount":0},{"title":"Does Ashwagandha supplementation have a beneficial effect on the management of anxiety and stress? A systematic review and meta-analysis","year":2022,"journal":"Phytotherapy Research","doi":"10.1002/ptr.7598","pmid":"36017529","url":"https://doi.org/10.1002/ptr.7598","studyDesign":"meta-analysis","fields":[],"conclusion":"Meta-analysis of 12 RCTs (1,002 participants) found ashwagandha significantly reduced anxiety and stress vs placebo. Certainty of evidence was rated low, warranting further high-quality studies. Doses of 300-600 mg/day appeared optimal for stress reduction; higher doses explored for anxiety.","abstract":"","citationCount":0},{"title":"Ashwagandha as a Unique Cause of Thyrotoxicosis Presenting With Supraventricular Tachycardia","year":2022,"journal":"Cureus","doi":"10.7759/cureus.23494","pmid":"35475098","url":"https://doi.org/10.7759/cureus.23494","studyDesign":"case-study","fields":[],"conclusion":"Case report of a 73-year-old woman who developed thyrotoxicosis and supraventricular tachycardia after two years of ashwagandha self-supplementation for hypothyroid symptoms. Symptoms fully resolved on discontinuation, establishing temporal causality. Highlights clinically significant thyroid interaction risk, particularly in patients with pre-existing thyroid conditions.","abstract":"","citationCount":0},{"title":"Effect of Ashwagandha (Withania somnifera) extract on sleep: A systematic review and meta-analysis","year":2021,"journal":"PLOS ONE","doi":"10.1371/journal.pone.0257843","pmid":"34554514","url":"https://doi.org/10.1371/journal.pone.0257843","studyDesign":"meta-analysis","fields":[],"conclusion":"Meta-analysis of 5 RCTs (400 participants) found ashwagandha extract produced a small but statistically significant improvement in overall sleep quality. Effects were stronger in adults with diagnosed insomnia, at doses ≥600 mg/day, and treatment ≥8 weeks. Mental alertness and anxiety also improved. Long-term safety data remain limited.","abstract":"","citationCount":0},{"title":"Effects of Ashwagandha (Withania somnifera) on Physical Performance: Systematic Review and Bayesian Meta-Analysis","year":2021,"journal":"Journal of Functional Morphology and Kinesiology","doi":"10.3390/jfmk6010020","pmid":"33670194","url":"https://doi.org/10.3390/jfmk6010020","studyDesign":"meta-analysis","fields":[],"conclusion":"Bayesian meta-analysis of 12 RCTs found ashwagandha supplementation superior to placebo for strength/power (medium effect), cardiorespiratory fitness (very large effect), and fatigue/recovery (large effect). VO2max and haemoglobin increased significantly at doses of 330-1000 mg/day over 8-24 weeks. Supports use for physical performance enhancement.","abstract":"","citationCount":0},{"title":"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","year":2021,"journal":"Journal of Ethnopharmacology","doi":"10.1016/j.jep.2020.113276","pmid":"32818573","url":"https://doi.org/10.1016/j.jep.2020.113276","studyDesign":"rct","fields":[],"conclusion":"8-week RCT of ashwagandha root extract (KSM-66, 600 mg/day) in 80 adults (healthy and insomnia patients) showed significant improvements in sleep onset latency, sleep efficiency, total sleep time, and anxiety on waking vs placebo. Benefits were greater in insomnia patients. Well-tolerated across all participants.","abstract":"","citationCount":0},{"title":"Effects of Ashwagandha (Withania somnifera) on VO2max: A Systematic Review and Meta-Analysis","year":2020,"journal":"Nutrients","doi":"10.3390/nu12041119","pmid":"32316411","url":"https://doi.org/10.3390/nu12041119","studyDesign":"meta-analysis","fields":[],"conclusion":"Meta-analysis of 4 RCTs (142 participants) found ashwagandha supplementation significantly improved VO2max by a mean of 3.00 mL/kg/min (95% CI: 0.18-5.82, p=0.04) in both athletes and non-athletes. Evidence quality was rated low due to small sample sizes and high heterogeneity (I²=84%). Further adequately powered RCTs recommended.","abstract":"","citationCount":0},{"title":"Liver Injury due to Ashwagandha. A Case Series from Iceland and the U.S. Drug-Induced Liver Injury Network","year":2020,"journal":"Liver International","doi":"10.1111/liv.14393","pmid":"31991029","url":"https://doi.org/10.1111/liv.14393","studyDesign":"case-study","fields":[],"conclusion":"Case series of 5 patients (3 Iceland, 2 US DILIN) demonstrated ashwagandha has hepatotoxic potential. Liver injury presented as cholestatic or mixed pattern with jaundice and pruritus, onset 2-12 weeks after starting supplementation. All cases were self-limited with liver tests normalising within 1-5 months. No cases progressed to hepatic failure.","abstract":"","citationCount":0},{"title":"An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: A randomized, double-blind, placebo-controlled study","year":2019,"journal":"Medicine (Baltimore)","doi":"10.1097/MD.0000000000017186","pmid":"31517876","url":"https://doi.org/10.1097/MD.0000000000017186","studyDesign":"rct","fields":[],"conclusion":"60-day RCT (n=60) of 240 mg Shoden ashwagandha extract found statistically significant reductions in HAM-A anxiety scores and morning serum cortisol vs placebo. DHEA-S also reduced. Proposed mechanism is modulation of the HPA axis. Well-tolerated with no serious adverse events. Supports use in stressed healthy adults.","abstract":"","citationCount":0},{"title":"A Randomized, Double-Blind, Placebo-Controlled, Crossover Study Examining the Hormonal and Vitality Effects of Ashwagandha (Withania somnifera) in Aging, Overweight Males","year":2019,"journal":"American Journal of Men's Health","doi":"10.1177/1557988319835985","pmid":"30854916","url":"https://doi.org/10.1177/1557988319835985","studyDesign":"rct","fields":[],"conclusion":"16-week crossover RCT (n=57) found 8 weeks of ashwagandha extract significantly increased salivary DHEA-S and testosterone in males aged 40-70, but did not significantly affect cortisol, estradiol, fatigue, or sexual well-being. Hormonal elevations did not translate clearly to symptomatic benefit in this older overweight cohort.","abstract":"","citationCount":0},{"title":"Effects of an Aqueous Extract of Withania somnifera on Strength Training Adaptations and Recovery: The STAR Trial","year":2018,"journal":"Nutrients","doi":"10.3390/nu10111807","pmid":"30463324","url":"https://doi.org/10.3390/nu10111807","studyDesign":"rct","fields":[],"conclusion":"12-week RCT of Sensoril (500 mg aqueous ashwagandha extract, roots+leaves) in 38 recreationally active men found significantly greater squat (+19.1 vs +10.0 kg) and bench press (+12.8 vs +8.0 kg) 1-RM gains vs placebo, improved body composition, and enhanced recovery perceptions. Well tolerated clinically. Key Sensoril-specific performance RCT.","abstract":"","citationCount":0},{"title":"Efficacy and Safety of Ashwagandha Root Extract in Subclinical Hypothyroid Patients: A Double-Blind, Randomized Placebo-Controlled Trial","year":2018,"journal":"Journal of Alternative and Complementary Medicine","doi":"10.1089/acm.2017.0183","pmid":"28829155","url":"https://doi.org/10.1089/acm.2017.0183","studyDesign":"rct","fields":[],"conclusion":"8-week pilot RCT (n=50) of 600 mg/day ashwagandha root extract in subclinical hypothyroid patients (TSH 4.5-10 μIU/L) found significant improvements in serum TSH, T3, and T4 vs placebo. Suggests ashwagandha may stimulate thyroid hormone synthesis. Clinicians should monitor thyroid function in patients on thyroid medications.","abstract":"","citationCount":0},{"title":"Examining the effect of Withania somnifera supplementation on muscle strength and recovery: a randomized controlled trial","year":2015,"journal":"Journal of the International Society of Sports Nutrition","doi":"10.1186/s12970-015-0104-9","pmid":"26609282","url":"https://doi.org/10.1186/s12970-015-0104-9","studyDesign":"rct","fields":[],"conclusion":"8-week RCT of KSM-66 (300 mg twice daily) in 57 untrained males found significantly greater gains in bench-press and leg-extension strength, muscle size, testosterone (+96 vs +18 ng/dL, p=0.004), and reduced exercise-induced muscle damage vs placebo. Concludes ashwagandha supplementation is beneficial alongside resistance training.","abstract":"","citationCount":0},{"title":"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","year":2012,"journal":"Indian Journal of Psychological Medicine","doi":"10.4103/0253-7176.106022","pmid":"23439798","url":"https://doi.org/10.4103/0253-7176.106022","studyDesign":"rct","fields":[],"conclusion":"64-participant, 60-day RCT of KSM-66 300 mg twice daily found significant reductions (p<0.0001) across all stress-assessment scales and substantially reduced serum cortisol vs placebo. Mild adverse effects comparable between groups. Concluded this full-spectrum root extract safely improves resistance to stress. Foundational KSM-66 RCT.","abstract":"","citationCount":0}]},"machineReadable":{"markdownUrl":"https://nutripedia.co.uk/items/ashwagandha/markdown","jsonUrl":"https://nutripedia.co.uk/items/ashwagandha/json","llmsTxt":"https://nutripedia.co.uk/llms.txt"},"disclaimer":"Informational supplement research only. Not medical advice. Consult a qualified healthcare professional before taking supplements.","lastReviewed":"2026-04-20T00:00:00.000Z","updatedAt":"2026-04-20T00:00:00.000Z"}