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Ashwagandha: Scored and Compared (2026)
Last reviewed: 2025-03-01 | 10 products scored | Clinical dose: 300-600mg daily of a standardized root extract (KSM-66 or Sensoril) | Prices checked: 2025-03-01
The Bottom Line
Ashwagandha (Withania somnifera) is one of the most studied adaptogenic herbs, with a growing body of clinical evidence particularly for stress and anxiety reduction. The research quality has improved significantly in the last decade with the availability of standardized extracts like KSM-66 and Sensoril. For stress and anxiety, a systematic review and meta-analysis by Pratte et al. Our top pick is KSM-66 Ashwagandha Extract 300mg (Grade: A, $0.25/day).
Quick Picks
What Is Ashwagandha?
Ashwagandha (Withania somnifera) is one of the most studied adaptogenic herbs, with a growing body of clinical evidence particularly for stress and anxiety reduction. The research quality has improved significantly in the last decade with the availability of standardized extracts like KSM-66 and Sensoril. For stress and anxiety, a systematic review and meta-analysis by Pratte et al. (2014) analyzed 5 RCTs and found that ashwagandha significantly reduced anxiety scores compared to placebo. Lopresti et al. (2019) conducted a 60-day RCT with 240 participants using KSM-66 (240mg/day) and found significant reductions in Hamilton Anxiety Rating Scale (HAM-A) scores, morning cortisol, and DHEA-S compared to placebo. Chandrasekhar et al. (2012) conducted a landmark 60-day RCT with 64 subjects using KSM-66 (300mg twice daily) and demonstrated a 27.9% reduction in serum cortisol levels and significant improvements in all stress assessment scales compared to placebo. For sleep, Langade et al. (2019) conducted a double-blind RCT with 150 participants using KSM-66 (300mg twice daily) and found significant improvements in sleep quality scores, sleep onset latency, and overall quality of life compared to placebo. Effects were more pronounced in the insomnia subgroup. For testosterone and male reproductive health, Lopresti et al. (2019) conducted a 16-week RCT showing KSM-66 supplementation increased testosterone levels by approximately 15% in overweight men aged 40-70. Wankhede et al. (2015) found that KSM-66 combined with resistance training significantly increased testosterone, muscle strength, and muscle size compared to placebo. For exercise performance, a systematic review by Bonilla et al. (2021) analyzed 12 RCTs and found that ashwagandha supplementation significantly improved VO2max and upper and lower body strength compared to placebo. The Sensoril extract has also shown efficacy - Auddy et al. (2008) found that Sensoril (125-250mg/day) significantly reduced serum cortisol and improved stress-resistance scores in a 60-day RCT.
Does It Work? The Evidence
| Claimed Benefit | Evidence Level | Key Studies | Our Verdict |
|---|---|---|---|
| Stress and cortisol reduction | Strong | 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 | Works |
| Anxiety reduction | Strong | Pratte et al. 2014 meta-analysis of 5 RCTs; multiple individual RCTs consistently show significant reduction in validated anxiety scales | Works |
| Sleep quality improvement | Moderate | Langade et al. 2019 double-blind RCT (n=150): significant improvements in sleep quality, onset latency, and restfulness with KSM-66 600mg/day | Promising |
| Testosterone and fertility (men) | Moderate | 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 | Promising |
| Exercise performance | Moderate | Bonilla et al. 2021 systematic review of 12 RCTs: significant improvements in VO2max and strength; effects modest but consistent | Promising |
| Cognitive function | Limited | Choudhary et al. 2017 RCT: KSM-66 improved memory, attention, and processing speed; promising but limited to a few small studies | Promising |
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)
Take 300-600mg of a KSM-66 extract daily, or 125-250mg of Sensoril daily. Can be taken with or without food. Many clinical trials used twice-daily dosing (e.g., 300mg morning and 300mg evening for KSM-66). For sleep benefits, consider evening dosing. For stress and anxiety, consistency matters more than timing - effects typically become noticeable after 4-8 weeks of daily use. Start at a lower dose and increase if well-tolerated. Allow 6-12 weeks for full effects.
The Scorecard: 10 Products Compared
KSM-66 Ashwagandha Extract 300mg
Nootropics Depot
Nootropics Depot is known in the supplement community for rigorous quality testing and genuine ingredient sourcing
KSM-66 is the most clinically studied ashwagandha extract with 24+ published clinical trials
Uses genuine KSM-66 with certificate of analysis available, third-party tested in-house and externally
$0.25/day at 600mg (2 capsules) - excellent value for genuine KSM-66
Full ingredient disclosure, KSM-66 certification, withanolide content specified on label
Prices checked 2025-03-01. Cost shown is per clinically effective daily dose, not per pill.
KSM-66 Ashwagandha 600mg
NutraBio
600mg per capsule means you only need 1 capsule for a full clinical dose
Full clinical dose of KSM-66 in a single capsule
Third-party tested with COAs publicly available on their website, GMP certified
$0.42/day at 600mg (1 capsule) - moderate pricing for the convenience of single-capsule dosing
Full ingredient disclosure, COAs published online, no proprietary blends, excipients listed
Prices checked 2025-03-01. Cost shown is per clinically effective daily dose, not per pill.
KSM-66 Ashwagandha 300mg
Jarrow FormulasWell-established supplement brand with a straightforward KSM-66 product at a competitive price
KSM-66 extract with the full clinical evidence base behind it
GMP facility, uses licensed KSM-66, no independent sport certification
$0.30/day at 600mg (2 capsules) - strong value for a branded KSM-66 product
Full disclosure of extract type, withanolide standardization, no proprietary blends
Prices checked 2025-03-01. Cost shown is per clinically effective daily dose, not per pill.
Optimized Ashwagandha (Sensoril)
Life ExtensionSensoril requires lower doses than KSM-66 due to higher withanolide concentration (10% vs 5%)
Sensoril extract (10% withanolides) has multiple RCTs supporting stress reduction and cortisol lowering
Life Extension uses third-party testing but does not hold NSF/USP sport certification
$0.35/day at 250mg (Sensoril clinical dose is 125-250mg due to higher withanolide concentration)
Full disclosure, Sensoril branding, withanolide standardization specified
Prices checked 2025-03-01. Cost shown is per clinically effective daily dose, not per pill.
Ashwagandha 450mg Standardized Extract
NOW FoodsBudget-friendly option, but note that generic extracts may not match the clinical results of KSM-66 or Sensoril
Generic standardized extract (2.5% withanolides) - less studied than KSM-66 or Sensoril
GMP certified facility, NPA A-rated, no third-party sport certification
$0.14/day at 450mg dose - very affordable option
Withanolide percentage disclosed, but not a branded extract so exact sourcing is less transparent
Prices checked 2025-03-01. Cost shown is per clinically effective daily dose, not per pill.
Ashwagandha 500mg
Pure EncapsulationsGood for people with sensitivities due to hypoallergenic formulation, but expensive for a non-branded extract
Generic root extract standardized to 2.5% withanolides - not a branded clinical extract
Hypoallergenic, GMP certified, third-party tested, free from common allergens
$0.52/day at 500mg - premium pricing for a generic extract
Full disclosure, free-from claims verified, no proprietary blends
Prices checked 2025-03-01. Cost shown is per clinically effective daily dose, not per pill.
Organic Ashwagandha 670mg
Himalaya
Himalaya is an established Ayurvedic company with decades of herbal supplement experience
Uses a proprietary CO2 extract standardized to withanolides, backed by Himalaya's own clinical studies
USDA Organic, Non-GMO Project Verified, GMP certified, in-house testing protocols
$0.28/day at 670mg - reasonable pricing for an organic product
Withanolide content specified, organic certification transparent, though not a widely studied branded extract
Prices checked 2025-03-01. Cost shown is per clinically effective daily dose, not per pill.
mykind Organics Ashwagandha
Garden of LifeGood for those who prioritize organic certification, but added ingredients may not provide additional benefit
Uses KSM-66 but combined with other botanical ingredients that add complexity without clear additive evidence
USDA Organic, Non-GMO Project Verified, but no third-party purity testing (USP/NSF)
$0.50/day - moderate pricing for a combination formula
KSM-66 amount is disclosed but additional botanicals add complexity; organic certifications are transparent
Prices checked 2025-03-01. Cost shown is per clinically effective daily dose, not per pill.
Ashwagandha Root Liquid Phyto-Caps
Gaia Herbs
Liquid phyto-cap format may offer better absorption for some, but the premium price is hard to justify vs. KSM-66 products
Generic root extract with withanolide standardization, not a branded clinical extract
Meets Identity Assured program (Gaia's in-house testing), purity tested, but no independent sport certification
$0.67/day - expensive for a generic extract without branded standardization
MeetYourHerbs traceability program shows sourcing, full ingredient disclosure, withanolide content on label
Prices checked 2025-03-01. Cost shown is per clinically effective daily dose, not per pill.
Ashwagandha 1000mg
Youtheory
High stated dose but without withanolide standardization it is unclear how this compares to standardized extracts
Generic extract, not a branded standardized form like KSM-66 or Sensoril
GMP facility, no independent third-party sport testing or certification
$0.23/day at 1000mg dose - affordable pricing
Withanolide standardization not prominently specified, no branded extract identification
Prices checked 2025-03-01. Cost shown is per clinically effective daily dose, not per pill.
Full Comparison
| Category | KSM-66 Ashwagandha Extract 300mg Nootropics Depot | KSM-66 Ashwagandha 600mg NutraBio | KSM-66 Ashwagandha 300mg Jarrow Formulas | Optimized Ashwagandha (Sensoril) Life Extension | Ashwagandha 450mg Standardized Extract NOW Foods | Ashwagandha 500mg Pure Encapsulations | Organic Ashwagandha 670mg Himalaya | mykind Organics Ashwagandha Garden of Life | Ashwagandha Root Liquid Phyto-Caps Gaia Herbs | Ashwagandha 1000mg Youtheory |
|---|---|---|---|---|---|---|---|---|---|---|
| Overall | A | A | A- | A- | B+ | B+ | B | B | B | B- |
| Evidence | A | A | A | A- | B | B | B | B | B | B |
| Quality & Purity | A- | A- | B | B | B | A- | B | B | B | C |
| Value | A | B | A | B | A | C | B | C | D | B |
| Transparency | A | A | A | A | B | A | B | B | A- | C |
| Cost/Day | $0.25 | $0.42 | $0.30 | $0.35 | $0.14Winner | $0.52 | $0.28 | $0.50 | $0.67 | $0.23 |
| Dose/Serving | 300mg | 600mg | 300mg | 125mg | 450mg | 500mg | 670mg | 600mg | 480mg | 1000mg |
| Form | KSM-66 Root Extract (5% withanolides) | KSM-66 Root Extract (5% withanolides) | KSM-66 Root Extract (5% withanolides) | Sensoril Root + Leaf Extract (10% 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 | Root Extract (liquid phyto-cap) | Root Extract (standardization not specified) |
| Third-Party Tested | ✓ Yes | ✓ Yes | No | ✓ Yes | No | ✓ Yes | No | No | ✓ Yes | No |
| Proprietary Blend | No | No | No | No | No | No | No | No | No | No |
Who Should Take Ashwagandha?
Adults experiencing chronic stress or elevated cortisol. People with mild to moderate anxiety (not a replacement for prescribed anxiolytics in severe cases). Those seeking improved sleep quality, especially stress-related sleep issues. Men interested in natural testosterone support (most evidence in overweight men 40+). Athletes looking for modest performance and recovery improvements.
Who Should Avoid It?
Pregnant or breastfeeding women (insufficient safety data). People with autoimmune thyroid conditions such as Hashimoto's (ashwagandha may increase thyroid hormone levels). Those on thyroid medications, immunosuppressants, sedatives, or blood sugar-lowering drugs without consulting a doctor first. People with liver conditions (rare case reports of liver injury). Anyone scheduled for surgery within 2 weeks (may affect anesthesia and blood sugar regulation). People with nightshade sensitivity (ashwagandha is in the nightshade family).
Side Effects & Safety
Generally well-tolerated. Most common side effects are mild GI discomfort (nausea, diarrhea) - usually resolves by taking with food. Drowsiness or sedation is more likely at higher doses or when combined with sedatives. Rare cases of liver injury have been reported in case studies, though a causal link has not been established in controlled trials. May increase thyroid hormone levels - monitor if you have thyroid conditions. Some people report vivid dreams.
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
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. J Clin Sleep Med. 2019;15(8):1119-1126.
- 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. JANA. 2008;11(1):50-56.
- NIH National Center for Complementary and Integrative Health. Ashwagandha - What You Need to Know.
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.