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Ashwagandha
Bottom line
In our scoring, Ashwagandha rates likely effective: the research is fairly solid for stress and cortisol reduction. Our top-scored product is KSM-66 Ashwagandha Extract 300mg (91/100), about $0.38 a day at a clinical dose of 300-600mg daily of a standardized root extract. Bottom line: a reasonable pick if it fits your goal. This is our opinion, not medical advice; talk to your clinician before starting.
Multiple trials measured the stress hormone cortisol directly and found it dropped 25-30% over 60 days, and a pooled analysis of 5 randomized trials confirmed real anxiety reduction against a placebo - which makes ashwagandha one of the few herbals where the clinical data actually holds up.
- Evidence
- Likely Effective
- Category
- Herbal & Botanical
- Best form
- KSM-66 (full-spectrum root extract, 5% withanolides)
- Effective dose
- 300-600mg daily of a standardized root extract (KSM-66 or Sensoril)
- Lab tested
- 5 of 10 products
- Category
- Herbal & Botanical
- Best form
- KSM-66 (full-spectrum root extract, 5% withanolides)
- Effective dose
- 300-600mg daily of a standardized root extract (KSM-66 or Sensoril)
- Lab tested
- 5 of 10 products
Key takeaways
- →Strong for stress and anxiety with ~25-30% cortisol reductions; sleep and testosterone effects are real but modest.
- →Use KSM-66 (5% withanolides) at 300-600mg/day or Sensoril (10% withanolides) at 125-250mg/day. Generic root powder is not interchangeable.
- →Nootropics Depot KSM-66 ($0.25/day) is the value pick; Life Extension Sensoril ($0.35/day) is the lower-dose alternative.
- →Skip if pregnant, on thyroid medication, or with a liver condition - rare case reports of liver injury warrant caution.
What Is Ashwagandha?
Multiple trials measured the stress hormone cortisol directly and found it dropped 25-30% over 60 days, and a pooled analysis of 5 randomized trials confirmed real anxiety reduction against a placebo - which makes ashwagandha one of the few herbals where the clinical data actually holds up. If you are stressed, anxious, or not sleeping well, this is the right page to be on. One thing to get right before anything else: buy KSM-66 or Sensoril (these are two specific branded, standardized extracts), not plain root powder. The cheap powder is a different product and has not been tested the same way.
The anxiety evidence is the strongest part. Several reviews pulling together multiple trials confirm a real reduction versus placebo, and what stands out is how consistent it is across different groups of people and different extracts. Both of the standardized forms - KSM-66 (made from root only) and Sensoril (root plus leaf) - calm anxiety to a similar degree.
Sleep is the next-best-supported benefit, though it sits a step behind. A well-run trial of 150 people found people fell asleep faster and slept better, and the effect was stronger in those who actually had insomnia to begin with. So if your stress is the kind that keeps you up, that is encouraging.
Testosterone and gym performance are where you should keep your expectations in check. Studies show roughly 15% testosterone increases, but mostly in narrow groups like overweight older men, not the average lifter. Exercise performance does improve, but by less than your feed would have you believe. Again: reach for KSM-66 or Sensoril, the two standardized extracts the clinical work was actually done on. Generic root powder is not the same product.
Does It Work? The Evidence
How A-F grades workAshwagandha earns a Likely Effective rating on the strength of its best-supported uses: stress and cortisol reduction and anxiety reduction (grade A). The table below grades every claimed benefit on its own, including weaker and more heavily marketed uses, so one strong result never stands in for the rest.
Stress and cortisol reduction
Chandrasekhar et al. 2012 RCT: 27.9% cortisol reduction with KSM-66; Lopresti et al. 2019 RCT (n=240): significant HAM-A improvement; Pratte 2014 meta-analysis of 5 RCTs
Anxiety reduction
Pratte et al. 2014 meta-analysis of 5 RCTs; multiple individual RCTs consistently show significant reduction in validated anxiety scales
Sleep quality improvement
Langade et al. 2019 double-blind RCT (n=150): significant improvements in sleep quality, onset latency, and restfulness with KSM-66 600mg/day
Testosterone and fertility (men)
Lopresti et al. 2019 16-week RCT: ~15% testosterone increase in overweight men 40-70; Wankhede et al. 2015: significant testosterone increase with resistance training
Exercise performance
Bonilla et al. 2021 systematic review of 12 RCTs: significant improvements in VO2max and strength; effects modest but consistent
Cognitive function
Choudhary et al. 2017 RCT: KSM-66 improved memory, attention, and processing speed; promising but limited to a few small studies
| Grade | Claimed Benefit | Key Studies | Our Verdict |
|---|---|---|---|
| A | Stress and cortisol reduction | Chandrasekhar et al. 2012 RCT: 27.9% cortisol reduction with KSM-66; Lopresti et al. 2019 RCT (n=240): significant HAM-A improvement; Pratte 2014 meta-analysis of 5 RCTs | Supported |
| A | Anxiety reduction | Pratte et al. 2014 meta-analysis of 5 RCTs; multiple individual RCTs consistently show significant reduction in validated anxiety scales | Supported |
| B | Sleep quality improvement | Langade et al. 2019 double-blind RCT (n=150): significant improvements in sleep quality, onset latency, and restfulness with KSM-66 600mg/day | Early Signal |
| B | Testosterone and fertility (men) | Lopresti et al. 2019 16-week RCT: ~15% testosterone increase in overweight men 40-70; Wankhede et al. 2015: significant testosterone increase with resistance training | Early Signal |
| B | Exercise performance | Bonilla et al. 2021 systematic review of 12 RCTs: significant improvements in VO2max and strength; effects modest but consistent | Early Signal |
| C | Cognitive function | Choudhary et al. 2017 RCT: KSM-66 improved memory, attention, and processing speed; promising but limited to a few small studies | Early Signal |
How to Choose: Forms, Doses & What Matters
Clinical dose: 300-600mg daily of a standardized root extract (KSM-66 or Sensoril)
Best forms: KSM-66 (full-spectrum root extract, 5% withanolides), Sensoril (root + leaf, 10% withanolides)
Your daily target is 300-600mg if you are using a KSM-66 extract, or 125-250mg if you are using Sensoril (Sensoril is more concentrated, which is why the number is lower). Food is optional - take it whenever fits your routine. A lot of the trials split the dose in two, for example 300mg in the morning and 300mg in the evening for KSM-66, so that is a fine way to do it. If sleep is your main goal, lean the dose toward the evening. For stress and anxiety, when you take it matters less than taking it every day - most people start noticing a difference after 4-8 weeks. Begin at the lower end, and step up if it sits well with you. Give it 6-12 weeks before you judge the full effect.
Who Should Take Ashwagandha?
This is a good fit if you are dealing with steady, ongoing stress or you suspect your cortisol runs high. It also suits mild to moderate anxiety, though if your anxiety is severe and you are on prescribed medication for it, this is an add-on to discuss with your doctor, not a swap. If you sleep badly because your mind will not switch off, the sleep evidence is in your corner. Men curious about a natural testosterone nudge can try it, but know the data is strongest in overweight men 40 and up. And if you train, expect modest gains in performance and recovery rather than a dramatic change.
Who Should Avoid It?
Not for everyone
Side Effects & Safety
Product Scores
10 products scored on dosing accuracy, third-party testing, cost per effective dose, and label transparency.
The Scorecard: 10 Products Compared
KSM-66 Ashwagandha Extract 300mg
Nootropics Depot$33.99 ÷ 89 days at 600mg/day (2 servings × 300mg)
Nootropics Depot is known in the supplement community for rigorous quality testing and genuine ingredient sourcing
Prices checked 2026-06-09. Cost shown is per clinically effective daily dose, not per pill.
KSM-66 Ashwagandha 300mg
Jarrow Formulas$17.99 ÷ 60 days at 600mg/day (2 servings × 300mg)
Well-established supplement brand with a straightforward KSM-66 product at a competitive price
Prices checked 2026-06-09. Cost shown is per clinically effective daily dose, not per pill.
KSM-66 Ashwagandha 600mg
NutraBio
$32.99 ÷ 89 days at 600mg/day (1 serving × 600mg)
600mg per capsule means you only need 1 capsule for a full clinical dose
Prices checked 2026-06-09. Cost shown is per clinically effective daily dose, not per pill.
Ashwagandha 450mg Standardized Extract
NOW Foods$15.00 ÷ 125 days at ~648mg/day (1.4 servings × 450mg)
Budget-friendly option, but note that generic extracts may not match the clinical results of KSM-66 or Sensoril
Prices checked 2026-06-09. Cost shown is per clinically effective daily dose, not per pill.
Ashwagandha 500mg
Pure Encapsulations$31.10 ÷ 60 days at 1000mg/day (2 servings × 500mg)
Good for people with sensitivities due to hypoallergenic formulation, but expensive for a non-branded extract
Prices checked 2026-03-01. Cost shown is per clinically effective daily dose, not per pill.
Organic Ashwagandha 670mg
Himalaya
$21.99 ÷ 59 days at 670mg/day (1 serving × 670mg)
Himalaya is an established Ayurvedic company with decades of herbal supplement experience
Prices checked 2026-06-09. Cost shown is per clinically effective daily dose, not per pill.
mykind Organics Ashwagandha
Garden of Life$18.00 ÷ 60 days at 600mg/day (1 serving × 600mg)
Good for those who prioritize organic certification, but added ingredients may not provide additional benefit
Prices checked 2026-06-09. Cost shown is per clinically effective daily dose, not per pill.
Optimized Ashwagandha (Sensoril)
Life Extension$7.50 ÷ 30 days at 250mg/day (2 servings × 125mg)
Sensoril requires lower doses than KSM-66 due to higher withanolide concentration (10% vs 5%)
Prices checked 2026-06-09. Cost shown is per clinically effective daily dose, not per pill.
Ashwagandha Root Liquid Phyto-Caps
Gaia Herbs$42.29 ÷ 60 days at 480mg/day (1 serving × 480mg)
Liquid phyto-cap format may offer better absorption for some, but the premium price is hard to justify vs. KSM-66 products
Prices checked 2026-06-09. Cost shown is per clinically effective daily dose, not per pill.
Ashwagandha 1000mg
Youtheory
$20.69 ÷ 90 days at 2000mg/day (2 servings × 1000mg)
High stated dose but without withanolide standardization it is unclear how this compares to standardized extracts
Prices checked 2026-03-01. Cost shown is per clinically effective daily dose, not per pill.
Full Comparison
| Category | KSM-66 Ashwagandha Extract 300mg Nootropics Depot | KSM-66 Ashwagandha 300mg Jarrow Formulas | KSM-66 Ashwagandha 600mg NutraBio | Ashwagandha 450mg Standardized Extract NOW Foods | Ashwagandha 500mg Pure Encapsulations | Organic Ashwagandha 670mg Himalaya | mykind Organics Ashwagandha Garden of Life | Optimized Ashwagandha (Sensoril) Life Extension | Ashwagandha Root Liquid Phyto-Caps Gaia Herbs | Ashwagandha 1000mg Youtheory |
|---|---|---|---|---|---|---|---|---|---|---|
| Brand Score | 91/100Winner | 90/100 | 90/100 | 86/100 | 83/100 | 80/100 | 79/100 | 77/100 | 73/100 | 70/100 |
| Dosing & Form | 25/25Winner | 25/25 | 25/25 | 25/25 | 25/25 | 25/25 | 25/25 | 14/25 | 25/25 | 25/25 |
| Purity | 22/25Winner | 19/25 | 22/25 | 19/25 | 22/25 | 19/25 | 19/25 | 19/25 | 19/25 | 13/25 |
| Value | 21/25 | 23/25Winner | 20/25 | 23/25 | 13/25 | 17/25 | 16/25 | 21/25 | 7/25 | 19/25 |
| Transparency | 23/25Winner | 23/25 | 23/25 | 19/25 | 23/25 | 19/25 | 19/25 | 23/25 | 22/25 | 13/25 |
| Cost/Day | $0.38 | $0.30 | $0.37 | $0.12Winner | $0.52 | $0.37 | $0.30 | $0.25 | $0.70 | $0.23 |
| Dose/Serving | 300mg | 300mg | 600mg | 450mg | 500mg | 670mg | 600mg | 125mg | 480mg | 1000mg |
| Form | KSM-66 Root Extract (5% withanolides) | KSM-66 Root Extract (5% withanolides) | KSM-66 Root Extract (5% withanolides) | Root Extract (2.5% withanolides) | Root Extract (2.5% withanolides) | Organic Root Extract + Supercritical CO2 Root Extract | KSM-66 Root Extract + Organic Ginger + Organic Probiotics | Sensoril Root + Leaf Extract (10% withanolides) | Root Extract (liquid phyto-cap) | Root Extract (standardization not specified) |
| Third-Party Tested | ✓ Yes | No | ✓ Yes | No | ✓ Yes | No | No | ✓ Yes | ✓ Yes | No |
| Proprietary Blend | No | No | No | No | No | No | No | No | No | No |
Frequently Asked Questions
What is the difference between KSM-66 and Sensoril?
Both are clinically studied standardized ashwagandha extracts, but they differ in composition. KSM-66 is a full-spectrum root extract standardized to 5% withanolides. Sensoril uses both root and leaf, standardized to 10% withanolides, so it requires a lower dose (125-250mg vs 300-600mg). Both have clinical evidence for stress reduction. KSM-66 has more published trials overall (24+).
When should I take ashwagandha - morning or night?
There is no definitive evidence that timing matters significantly. For stress and anxiety, many people take it in the morning. For sleep benefits, taking it in the evening may be preferable. Some studies used twice-daily dosing (300mg morning and evening). Consistency matters more than timing.
How long does ashwagandha take to work?
Most clinical trials showing significant effects ran for 8-12 weeks. Some participants notice reduced stress within 2-4 weeks, but the full benefit typically develops over 6-12 weeks of consistent daily use. Do not expect immediate effects.
Can ashwagandha cause liver damage?
There have been rare case reports of liver injury associated with ashwagandha, which led to regulatory attention in some countries. However, controlled clinical trials have not found liver toxicity at standard doses. If you have pre-existing liver conditions, consult your doctor before use and monitor liver enzymes.
Is ashwagandha safe to take with medications?
Ashwagandha may interact with thyroid medications (it can increase thyroid hormone levels), immunosuppressants, sedatives, and blood sugar-lowering drugs. It should be discontinued 2 weeks before surgery. Always consult your doctor if you take any medications.
Why are some ashwagandha products so much cheaper than others?
The biggest cost driver is whether the product uses a branded, standardized extract (KSM-66, Sensoril) vs. a generic extract. Branded extracts undergo additional quality control and standardization, and the manufacturers invest in clinical trials. Generic extracts may vary in withanolide content and have not been directly studied in RCTs.
Related Supplements
Related Reading
Related Articles
Sources
- Pratte MA, et al. An alternative treatment for anxiety: a systematic review of human trial results reported for the Ayurvedic herb ashwagandha. J Altern Complement Med. 2014;20(12):901-8.
- 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. Indian J Psychol Med. 2012;34(3):255-62.
- Lopresti AL, et al. An investigation into the stress-relieving and pharmacological actions of an ashwagandha extract. Medicine. 2019;98(37):e17186.
- Langade D, et al. Clinical evaluation of the pharmacological impact of ashwagandha root extract on sleep in healthy volunteers and insomnia patients. Cureus. 2019;11(9):e5797.
- Wankhede S, et al. Examining the effect of Withania somnifera supplementation on muscle strength and recovery: a randomized controlled trial. J Int Soc Sports Nutr. 2015;12:43.
- Bonilla DA, et al. Effects of Ashwagandha on Physical Performance: Systematic Review and Bayesian Meta-Analysis. J Funct Morphol Kinesiol. 2021;6(1):20.
- Auddy B, et al. A standardized Withania somnifera extract significantly reduces stress-related parameters in chronically stressed humans: a double-blind, randomized, placebo-controlled study. J Am Nutr Assoc (JANA). 2008;11(1):50-56. (Not PubMed-indexed.)
- NIH National Center for Complementary and Integrative Health. Ashwagandha - What You Need to Know.
Scores and tiers are our independent opinion, formed by applying a published rubric to label data, third-party certifications, and the research record. They are not statements of objective fact about a product and not a lab test. Where we report a brand-specific fact, it comes from a cited source or a public certification; where verification is missing, we say so rather than assume a result.
FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. The products discussed on this page are not intended to diagnose, treat, cure, or prevent any disease. Always consult with a qualified healthcare professional before starting any supplement regimen.