Strength
Ashwagandha root extract (KSM-66)
KSM-66 ashwagandha is a root extract with strength and VO2max data from weeks of daily use.
How it counts: Not part of the score
We show it on the label and count it as disclosed, but it never affects Dose, any sub-score or the grade. The basis below explains why.
- Clinical dose
- No established clinical dose
- Safety ceiling
- —
- Evidence
- moderate
- Category
- Strength
Evidence summary
Research confidence: medium
No pre-workout reference dose. KSM-66 is a root-only ashwagandha extract sold for strength, recovery and stress. In 57 young men starting resistance training, 300 mg twice a day (600 mg/day) for 8 weeks gave larger bench-press and leg-extension gains than placebo (Wankhede 2015), and the same daily amount for 12 weeks raised VO2max in athletic adults (Choudhary 2015). Those results come from 600 mg a day taken for weeks; a 100 mg scoop before training is a sixth of that and not the daily use the studies tested.
Research sources
- Examining the effect of Withania somnifera supplementation on muscle strength and recovery: a randomized controlled trial (Wankhede et al., JISSN 2015)(opens in new window)
- Efficacy of Ashwagandha (Withania somnifera [L.] Dunal) in improving cardiorespiratory endurance in healthy athletic adults (Choudhary et al., AYU 2015)(opens in new window)
50 athletic adults, double-blind: 300 mg root extract twice a day (600 mg/day) for 12 weeks raised VO2max more than placebo.
- Effects of Withania somnifera (Ashwagandha) Supplementation on Exercise Performance: A Systematic Review and Three-Level Meta-Analysis (Li et al., Nutrients 2026)(opens in new window)
13 RCTs, 599 participants: overall performance g=0.47 (prediction interval crosses zero); clearest for aerobic endurance; strength effects positive but uncertain; 500-600 mg/day the most evidence-supported extract dose.
- Ashwagandha-induced acute liver injury: A case report (Tóth et al., Clin Case Rep 2023)(opens in new window)
Rare liver-injury case reports exist for ashwagandha supplements; recovery after stopping.