KSM-66 vs Sensoril: Which Ashwagandha Extract Should You Take?

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The key difference is the plant part and the dose. KSM-66 is a root-only extract standardized to at least 5% withanolides, and most of its trials used 600 mg a day (300 mg twice daily). Sensoril combines root and leaf, is standardized to at least 10% withanolide glycosides and is typically taken at 125–250 mg a day (its main trials used up to 500 mg).

KSM-66 has more published trials, including the main sleep studies; most of the evidence for Sensoril is about stress. No published trial has compared the two directly, so choose by goal and take the dose tested for that extract. The ashwagandha dosage calculator gives a dose for each.

What KSM-66 and Sensoril are

KSM-66: root only, at least 5% withanolides

KSM-66 is made by Ixoreal Biomed in India, which describes it as a full-spectrum, root-only extract made with a “Green Chemistry” process that uses no alcohol or other chemical solvents. Trial reports describe it as standardized to at least 5% withanolides, measured by HPLC (Chandrasekhar et al., 2012; Wankhede et al., 2015). In a dose comparison, 250 mg a day still lowered perceived stress and cortisol, but only 600 mg a day improved every measure the trial used (Salve et al., 2019).

Sensoril: root and leaf, at least 10% withanolide glycosides

Sensoril was developed by Natreon, which now belongs to Kerry Group. It is a water-based extract of root and leaf, described in trial reports as standardized to at least 10% withanolide glycosides, at least 32% oligosaccharides and no more than 0.5% withaferin A (Pingali et al., 2014; Ramakanth et al., 2016). Its main stress trial compared 125, 250 and 500 mg a day (Pandit et al., 2024), and a strength trial used 500 mg a day (Ziegenfuss et al., 2018). Kerry’s technical brochure lists 125 and 250 mg a day.

Why 10% does not mean twice as strong

The labels measure different things: KSM-66 reports total withanolides, Sensoril reports withanolide glycosides, and the root and leaf of the plant have different chemical profiles (NIH Office of Dietary Supplements). Compare your daily amount with the trial dose for that specific extract, not the percentage on the bottle. Ixoreal argues that the root is the traditional, pharmacopoeia-listed part; Kerry argues that adding leaf gives a broader range of compounds at a lower dose. No head-to-head trial has tested either claim.

KSM-66 vs Sensoril at a glance

What the studies show for KSM-66

• Stress and cortisol. In 64 adults with chronic stress, 300 mg twice a day for 60 days lowered perceived-stress scores by 44% (5.5% with placebo) and serum cortisol by 27.9% (7.9% with placebo) (Chandrasekhar et al., 2012).
• Sleep. In 60 adults with insomnia, the same dose for 10 weeks cut the time to fall asleep to 29.0 minutes, against 33.9 with placebo (Langade et al., 2019). A second trial in 80 adults found larger gains in people with insomnia than in healthy volunteers (Langade et al., 2021). A meta-analysis of five trials with 400 adults found a small but significant effect on sleep, stronger at 600 mg a day or more and after at least 8 weeks (Cheah et al., 2021).
• Strength and testosterone. In 57 young men new to weight training, 600 mg a day for 8 weeks gave bigger bench-press gains than placebo (46.0 vs 26.4 kg) and a larger rise in testosterone (96.2 vs 18.0 ng/dL) (Wankhede et al., 2015). The NIH’s National Center for Complementary and Integrative Health (NCCIH) still rates the evidence for athletic performance as insufficient and for testosterone as limited.

These trials were run in India with 57 to 80 people over 8 to 10 weeks. Where the full text is public, Ixoreal supplied the extract and the authors declared no competing interests.

What the studies show for Sensoril

• Stress and cortisol. The largest trial randomized 131 stressed adults to 125, 250 or 500 mg a day or placebo, taken about 30 minutes before bed for 8 weeks; 98 were included in the final analysis. All three doses lowered perceived stress, plasma cortisol and ACTH more than placebo. Natreon funded the study, and many participants dropped out during the COVID-19 pandemic (Pandit et al., 2024).
• Strength. In 38 recreationally active men on a 12-week lifting program, 500 mg each morning raised the squat one-rep max by 19.1 kg (10.0 kg with placebo) and the bench press by 12.8 kg (8.0 kg). Natreon funded the trial (Ziegenfuss et al., 2018).
• Reaction time. In a 14-day crossover study of 20 healthy men, 1,000 mg a day improved reaction times on several computer tests; Natreon supplied the capsules (Pingali et al., 2014).
• Sleep. None of the five trials in the 2021 sleep meta-analysis used Sensoril. In the 2024 stress trial, sleep-quality scores improved more than with placebo, but only as a secondary outcome.

Sensoril has fewer trials in healthy adults than KSM-66, and all three above were funded by Natreon or used its capsules. Its practical advantage is the smaller dose.

Which extract fits your goal

For stress and cortisol

Both extracts have placebo-controlled trials showing lower perceived stress and cortisol after about 8 weeks. KSM-66 has more: in a 2021 systematic review of seven stress trials, three used KSM-66 and two used root-and-leaf extracts, Sensoril or Shoden (NIH Office of Dietary Supplements). Either is a reasonable choice at its trial dose.

For sleep

KSM-66 is the better-supported option: the sleep trials used 600 mg a day for 8 to 10 weeks, and the benefit was modest and larger in people with insomnia. More on timing: ashwagandha for sleep.

For strength training

Each extract has one small trial in men who lifted weights, and both found larger strength gains than placebo. NCCIH rates this evidence as insufficient.

Safety: the same cautions apply to both

Official guidance covers ashwagandha in general, not each extract.

• Short-term use. NCCIH says ashwagandha may be safe for up to 3 months and that its long-term safety is unknown; the NIH Office of Dietary Supplements says it appears well tolerated for up to about 3 months. Drowsiness, stomach upset, diarrhea and vomiting have been reported.
• Liver. LiverTox rates ashwagandha as a likely (category B) cause of rare, clinically apparent liver injury, which usually appears 2 to 12 weeks after starting, with jaundice and itching (LiverTox; Björnsson et al., 2020). Stop taking it and see a doctor if you notice yellow skin or eyes, dark urine or itching, and avoid it if you have cirrhosis or advanced liver disease.
• Pregnancy and breastfeeding. NCCIH says ashwagandha should be avoided during pregnancy and should not be used while breastfeeding.
• Thyroid. In 50 adults with subclinical hypothyroidism, a root extract at 600 mg a day for 8 weeks raised T3 and T4 and lowered TSH (Sharma et al., 2018), and three people taking 500 mg a day of Sensoril had small rises in T4 (Gannon et al., 2014). NCCIH does not recommend ashwagandha for people with thyroid disorders, and it may interact with thyroid hormone medication.
• Autoimmune conditions and surgery. NCCIH does not recommend it for people with autoimmune disease or for anyone about to have surgery.
• Medications. It may interact with sedatives, anti-seizure drugs, immunosuppressants and medicines for diabetes, blood pressure or the thyroid (NCCIH). If you take any of them, ask your doctor or pharmacist first.
• Hormone-sensitive prostate cancer. Because ashwagandha may raise testosterone, NCCIH says people with this condition should avoid it.

How to choose a product

1. Start with your goal. For sleep, the evidence points to KSM-66; for stress, either extract has trials behind it.
2. Check the extract name and plant part. The label should name KSM-66 (root) or Sensoril (root and leaf); generic root powder is not what these trials used.
3. Add up the daily amount. Aim for the trial dose: about 600 mg a day of KSM-66, split into two doses, or 125–250 mg a day of Sensoril.
4. Read blends carefully. A “proprietary blend” may list only its total weight, not how much ashwagandha it contains.
5. Look for a quality seal. Seals from USP, NSF or ConsumerLab.com confirm that a product contains what the label says without harmful levels of contaminants, not that it is safe or effective (NIH Office of Dietary Supplements).

Browse KSM-66 ashwagandha on Amazon

Browse Sensoril ashwagandha on Amazon

Next steps: get your dose from the ashwagandha dosage calculator, read the complete ashwagandha guide, or see ashwagandha for sleep.

Sources

1. 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 in adults. Indian J Psychol Med. 2012;34(3):255-62. PMID 23439798
2. Salve J, Pate S, Debnath K, Langade D. Adaptogenic and anxiolytic effects of ashwagandha root extract in healthy adults. Cureus. 2019;11(12):e6466. PMID 32021735
3. Langade D, Kanchi S, Salve J, Debnath K, Ambegaokar D. Efficacy and safety of ashwagandha (Withania somnifera) root extract in insomnia and anxiety. Cureus. 2019;11(9):e5797. PMID 31728244
4. Langade D, Thakare V, Kanchi S, Kelgane S. Clinical evaluation of the pharmacological impact of ashwagandha root extract on sleep in healthy volunteers and insomnia patients. J Ethnopharmacol. 2021;264:113276. PMID 32818573
5. Cheah KL, Norhayati MN, Husniati Yaacob L, Abdul Rahman R. Effect of ashwagandha (Withania somnifera) extract on sleep: a systematic review and meta-analysis. PLoS One. 2021;16(9):e0257843. PMID 34559859
6. Wankhede S, Langade D, Joshi K, Sinha SR, Bhattacharyya S. Examining the effect of Withania somnifera supplementation on muscle strength and recovery: a randomized controlled trial. J Int Soc Sports Nutr. 2015;12:43. PMID 26609282
7. Pandit S, Srivastav AK, Sur TK, Chaudhuri S, Wang Y, Biswas TK. Effects of Withania somnifera extract in chronically stressed adults: a randomized controlled trial. Nutrients. 2024;16(9):1293. PMID 38732539
8. Ziegenfuss TN, Kedia AW, Sandrock JE, Raub BJ, Kerksick CM, Lopez HL. Effects of an aqueous extract of Withania somnifera on strength training adaptations and recovery: the STAR trial. Nutrients. 2018;10(11):1807. PMID 30463324
9. Pingali U, Pilli R, Fatima N. Effect of standardized aqueous extract of Withania somnifera on tests of cognitive and psychomotor performance in healthy human participants. Pharmacognosy Res. 2014;6(1):12-8. PMID 24497737
10. Ramakanth GS, Uday Kumar C, Kishan PV, Usharani P. A randomized, double blind placebo controlled study of efficacy and tolerability of Withania somnifera extracts in knee joint pain. J Ayurveda Integr Med. 2016;7(3):151-7. PMID 27647541
11. Sharma AK, Basu I, Singh S. Efficacy and safety of ashwagandha root extract in subclinical hypothyroid patients. J Altern Complement Med. 2018;24(3):243-8. PMID 28829155
12. Gannon JM, Forrest PE, Roy Chengappa KN. Subtle changes in thyroid indices during a placebo-controlled study of an extract of Withania somnifera in persons with bipolar disorder. J Ayurveda Integr Med. 2014;5(4):241-5. PMID 25624699
13. 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;40(4):825-9. PMID 31991029
14. LiverTox: Ashwagandha. National Institute of Diabetes and Digestive and Kidney Diseases; last updated December 3, 2024. NBK548536
15. National Center for Complementary and Integrative Health. Ashwagandha (last updated March 2023). nccih.nih.gov
16. NIH Office of Dietary Supplements. Ashwagandha: Is it helpful for stress, anxiety, or sleep? Fact sheet for health professionals (updated May 2, 2025). ods.od.nih.gov
17. NIH Office of Dietary Supplements. Dietary Supplements: What You Need to Know (updated January 4, 2023). ods.od.nih.gov
18. Ixoreal Biomed. What is KSM-66. ksm66ashwagandhaa.com
19. Kerry. Sensoril technical brochure (2025). supplements.kerry.com

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