Ashwagandha Dosage Guide: How Much to Take (by Extract and Goal)
Not medical advice — this summarizes published research. Ashwagandha has a real (if uncommon) liver-safety signal and several drug and condition cautions below; talk to a clinician before starting, especially if you take medication or have a liver, thyroid, or autoimmune condition. Methodology.
Clinical trials use 120–600 mg/day of a standardized extract — not grams of raw powder — and the effective dose depends on which extract you have and what you want. The workhorse protocol is 300 mg of KSM-66 twice a day (PMID 23439798); higher-concentration root+leaf extracts are studied at just 120–240 mg. The evidence is genuinely strong for stress and sleep, but only preliminary for testosterone and muscle — and there's a real, if uncommon, liver caution you should know first.
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Quick answer: match the dose to a real trial. For stress or sleep, 300 mg of KSM-66 twice daily (or 120–240 mg of a Sensoril/Shoden-type extract) is the studied range. Ignore the milligram number on a bottle that doesn't name a standardized extract and a withanolide percentage — it can't be mapped to any study. Use the tool below to see the exact dose, extract, and trial length for your specific goal.
What dose was actually studied for your goal?
Ashwagandha's "right dose" isn't one number — it's whatever the trial for your goal used. Pick a goal to see the exact dose, the standardized extract, how long the study ran, and how strong the evidence is.
Why "500 mg ashwagandha" tells you almost nothing
This is the single thing most ashwagandha advice gets wrong. Three completely different products get sold under the same "ashwagandha" label, and a milligram number can't distinguish them:
- Raw root powder — traditional Ayurvedic use, dosed in grams (3–6 g/day), not standardized to any active-compound level. This is not what the clinical trials tested, so "500 mg" of it is a small, sub-clinical amount.
- KSM-66 — a root-only extract standardized to roughly 5% withanolides; the most-studied branded extract, dosed at 300–675 mg/day in trials (PMID 23439798).
- Sensoril / Shoden-type — root+leaf extracts standardized to a much higher withanolide-glycoside content (Sensoril ~10%, Shoden ~35%), so they're studied at lower doses (120–240 mg/day) (PMID 32540634).
Because the extracts are standardized differently, the same withanolide dose can appear as a very different milligram dose. So a label reading "500 mg ashwagandha extract" with no named extract and no withanolide percentage can't be matched to any study — that's the difference between an evidence-based purchase and a guess. Our KSM-66 vs Sensoril comparison breaks down which extract fits which goal.
Ashwagandha dose by goal
Every row is a dose that was actually used in a published trial. Doses aren't interchangeable across extract brands.
| Goal | Studied dose | Extract · duration · evidence |
|---|---|---|
| Stress & anxiety | 300 mg 2×/day (or 240 mg 1×) | KSM-66, 60 days (23439798); Shoden 240 mg (31517876). Strong — backed by a 12-RCT meta-analysis (36017529). |
| Sleep quality | 600 mg/day (or 120 mg 1×) | KSM-66, 10 weeks (31728244); Shoden 120 mg, 6 weeks (32540634). Strong in adults with disrupted sleep. |
| Lower cortisol | 300 mg 2×/day | KSM-66, 60 days — cortisol fell ~28% from baseline vs ~8% on placebo (23439798). Moderate. |
| Testosterone / male fertility | 675 mg/day (3×225 mg) | KSM-66, 90 days in oligospermic men (24371462); a Shoden crossover delivering ~21 mg withanolide glycosides/day (30854916). Preliminary — meta-analysis calls evidence too limited (30466985). |
| Strength / exercise recovery | 300 mg 2×/day | KSM-66, 8 weeks (26609282). Preliminary — one small industry-affiliated RCT. |
| Memory / cognition | 300 mg 2×/day | Root extract, 8 weeks in mild cognitive impairment (28471731). Preliminary — small pilot, not yet replicated. |
Safety: the liver signal, thyroid, and who should skip it
Ashwagandha can, rarely, injure the liver — this is the one to take seriously. The NIH LiverTox database rates ashwagandha a "likely but uncommon" cause of clinically apparent liver injury (LiverTox, NBK548536). Two published case series describe a cholestatic injury pattern — jaundice, itching, nausea — that typically appeared within 2–12 weeks of starting and resolved after stopping, though rare severe cases occurred (PMID 31991029, PMID 37756041). If you have existing liver disease, don't take it. If you develop jaundice, dark urine, or persistent nausea while taking it, stop and see a doctor.
- Thyroid: ashwagandha can raise thyroid hormone (T3/T4) and lower TSH — a trial in subclinical hypothyroidism showed measurable shifts (PMID 28829155). Helpful for some, but a reason for caution if you have any thyroid condition or take thyroid medication — coordinate with your doctor.
- Pregnancy & breastfeeding: NIH's NCCIH advises avoiding ashwagandha if you're pregnant or breastfeeding.
- Autoimmune conditions: it may stimulate immune activity, so caution if you have an autoimmune disease or take immunosuppressants; NCCIH also suggests stopping before surgery.
- Hormone-sensitive prostate cancer: because ashwagandha can raise testosterone in some trials, NCCIH advises men with hormone-sensitive prostate cancer to avoid it.
- Drug interactions: can add to sedatives, and to thyroid, blood-sugar-lowering, blood-pressure-lowering, immunosuppressant, and anti-seizure (anticonvulsant) medications. Check with a clinician if you take any of these.
Timing, food, and the cycling myth
- Time of day: no trial directly compares morning vs. evening. Sleep studies dosed it in the evening, so evening is reasonable for sleep; stress trials split the dose morning and night. Pick what fits your goal.
- With food: not required by any trial, but taking it with a meal can reduce the mild GI upset some people get.
- Cycling isn't evidence-based. "8 weeks on, 2 weeks off" is a supplement-industry convention — no trial in the table above tested a cycling protocol against continuous use. Trials simply dosed continuously for 6–16 weeks. If you stop, adverse effects (when they occur) generally reverse.
How strong is the evidence, honestly?
Ashwagandha is one of the better-studied adaptogens, but the evidence is uneven, so it's worth being precise:
- Strong — stress, anxiety, and sleep. A 12-RCT meta-analysis supports a real reduction in perceived stress and anxiety, though its authors rate the certainty of the evidence as low (PMID 36017529). Sleep quality is supported separately by two randomized trials (31728244, 32540634) — a genuine effect, not a huge one.
- Preliminary — testosterone, fertility, strength, cognition. Individual small trials are positive, but they're short, small, frequently manufacturer-funded, and a dedicated fertility meta-analysis calls the evidence too limited to be conclusive (PMID 30466985). Read these as "an early trial found," not "proven."
Frequently asked questions
How much ashwagandha should I take per day?
Trials use 120–600 mg/day of a standardized extract, not grams of powder. The common protocol is 300 mg of KSM-66 twice daily (600 mg/day); higher-concentration Sensoril/Shoden extracts are studied at 120–240 mg/day. The right number depends on your extract and goal.
Is 500 mg of ashwagandha a good dose?
It depends entirely on the extract — which is the problem with that number. It could be raw powder (too little), KSM-66 (reasonable), or a high-concentration extract (more than the studied 120–240 mg). Check the named extract and withanolide %, not just the milligrams.
Does ashwagandha affect the liver?
Rarely, but it's documented. NIH's LiverTox lists it as an uncommon but likely cause of liver injury, and case series describe cholestatic injury that usually appeared within 2–12 weeks and resolved after stopping. Avoid it if you have liver disease; stop and see a doctor if you develop jaundice or dark urine.
When should I take ashwagandha — morning or night?
No trial compares the two directly. Sleep studies dosed it in the evening; stress trials split the dose. Take it with food if it upsets your stomach. Cycling on and off is industry convention, not something trials tested.
Does ashwagandha really raise testosterone?
The evidence is preliminary. A few small KSM-66 trials in men found increases, but a meta-analysis calls the evidence too limited to be conclusive, and many trials are small and manufacturer-funded. The strong evidence is for stress and sleep, not hormones.
Who should not take ashwagandha?
People who are pregnant or breastfeeding, anyone with liver disease, people with thyroid or autoimmune conditions or on related medication, and anyone scheduled for surgery. It can also interact with sedatives and blood-sugar/blood-pressure drugs — check with a clinician.
Related guides
- KSM-66 vs Sensoril — which extract for which goal · Best ashwagandha overall
- Best ashwagandha for anxiety & stress · Best ashwagandha for sleep
Sources
- 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. Indian J Psychol Med. 2012. PMID: 23439798
- Lopresti AL, Smith SJ, Malvi H, Kodgule R. An investigation into the stress-relieving and pharmacological actions of an ashwagandha extract. Medicine (Baltimore). 2019. PMID: 31517876
- Langade D, Kanchi S, Salve J, et al. Efficacy and Safety of Ashwagandha Root Extract in Insomnia and Anxiety. Cureus. 2019. PMID: 31728244
- Deshpande A, Irani N, Balkrishnan R, Benny IR. A randomized, double blind, placebo controlled study to evaluate the effects of ashwagandha on sleep quality. Sleep Med. 2020. PMID: 32540634
- Akhgarjand C, Asoudeh F, Bagheri A, et al. Does ashwagandha supplementation have a beneficial effect on anxiety and stress? A meta-analysis. Phytother Res. 2022. PMID: 36017529
- Ambiye VR, Langade D, Dongre S, et al. Clinical Evaluation of the Spermatogenic Activity of the Root Extract of Ashwagandha in Oligospermic Males. Evid Based Complement Alternat Med. 2013. PMID: 24371462
- Lopresti AL, Drummond PD, Smith SJ. A Randomized, Double-Blind, Placebo-Controlled, Crossover Study Examining the Hormonal and Vitality Effects of Ashwagandha in Aging, Overweight Males. Am J Mens Health. 2019. PMID: 30854916
- Durg S, Shivaram SB, Bavage S. Withania somnifera (Indian ginseng) in male infertility: A systematic review and meta-analysis. Phytomedicine. 2018. PMID: 30466985
- Wankhede S, Langade D, Joshi K, et al. Examining the effect of Withania somnifera supplementation on muscle strength and recovery. J Int Soc Sports Nutr. 2015. PMID: 26609282
- Choudhary D, Bhattacharyya S, Bose S. Efficacy and Safety of Ashwagandha Root Extract in Improving Memory and Cognitive Functions. J Diet Suppl. 2017. PMID: 28471731
- Sharma AK, Basu I, Singh S. Efficacy and Safety of Ashwagandha Root Extract in Subclinical Hypothyroid Patients. J Altern Complement Med. 2018. PMID: 28829155
- Björnsson HK, Björnsson ES, Avula B, et al. Ashwagandha-induced liver injury: A case series from Iceland and the US Drug-Induced Liver Injury Network. Liver Int. 2020. PMID: 31991029
- Philips CA, Theruvath AH, Ravindran R, et al. Ashwagandha-induced liver injury—a case series from India and literature review. Hepatol Commun. 2023. PMID: 37756041
- NIH LiverTox: Clinical and Research Information on Drug-Induced Liver Injury — Ashwagandha. NCBI Bookshelf. NBK548536
- NIH National Center for Complementary and Integrative Health (NCCIH). Ashwagandha: Usefulness and Safety. nccih.nih.gov