KSM-66® ashwagandha improves strength, muscle size, and testosterone in resistance-trained men
Published 2015
Study Design
- Population
- 57 healthy young men undergoing resistance training
- Design
- Randomized, double-blind, placebo-controlled, parallel-group
- Dosage
- 600 mg/day KSM-66 (300 mg BID)
- Duration
- 8 weeks
Citation
Journal of the International Society of Sports Nutrition (2015).
Authors: Kean Wankhede, et al.
Affiliation: Sports Science & Nutrition Research centers (India/US)
Plain takeaway
In trained men, KSM-66 improved strength, muscle size, and testosterone compared with placebo across 8 weeks.
Study context
Hypothesis: Ashwagandha root extract (KSM-66) improves training adaptations compared with placebo.
Objective: To assess effects of KSM-66 (300 mg twice daily) on muscle strength, size, recovery, and serum hormones.
Methods & Controls
Supervised resistance training program; outcomes included 1-RM bench/squat, muscle cross-sectional area, body composition, serum testosterone, and muscle damage markers.
Controls: Matching placebo; allocation concealed; participants/investigators blinded.
Key outcomes
- ↑ 1-RM bench & squat vs placebo
- ↑ Muscle size (arm/chest) vs placebo
- ↑ Serum testosterone vs placebo
- ↓ Exercise-induced muscle damage markers
Summary & Interpretation
In a supervised 8-week resistance training program (n≈57), KSM-66 ashwagandha (600 mg/day) improved maximal strength (bench and squat), increased muscle size, elevated serum testosterone, and reduced markers of exercise-induced muscle damage versus placebo. Findings support an ergogenic role for standardized ashwagandha in trained young men, with the caveat of brand-specificity and limited generalizability.