Ashwagandha for athletic performance: strength, recovery, and VO2max evidence
Ashwagandha for athletic performance: strength, recovery, and VO2max in randomized trials
Time to effect
Dose
Active compound
▪ The challenge at hand
Beyond its stress and sleep effects, ashwagandha has a separate, well-replicated body of evidence in athletic populations. A randomized controlled trial in men undergoing resistance training found that 600mg/day of ashwagandha led to significantly greater gains in bench press and leg extension strength, larger increases in muscle size, and lower markers of exercise-induced muscle damage compared with placebo, with a meaningfully faster recovery between training sessions.
Separate trials have found improvements in VO2max, a key measure of cardiorespiratory endurance, in both untrained adults and recreational athletes. The proposed mechanism involves its effect on testosterone (which rose meaningfully in the resistance training trial), cortisol reduction during exercise, and antioxidant effects that reduce the inflammatory and oxidative load of training. This is a different angle on the same supplement, but it deserves its own conversation because the population, the protocol, and the expected readout are all distinct from the stress and sleep use cases.
▪ What it is
Standardized ashwagandha root extract (KSM-66), taken twice daily for at least 8 weeks alongside a consistent training program, studied for improving strength gains, muscle recovery, and cardiorespiratory endurance in active adults.
▪ Why this is surprising
Ashwagandha is most associated with stress and sleep, but a separate body of sports-specific RCTs finds real effects on muscle strength and mass gains, muscle damage recovery, and VO2max in resistance-trained and recreationally active populations. A randomized trial in resistance-training men found significantly greater strength gains, more muscle mass, and lower muscle damage markers at the same training volume. The mechanism, cortisol reduction during exercise plus testosterone support plus antioxidant reduction of training-induced oxidative stress, is distinct from its stress axis action.
▪ How it works
Amplifying what training builds.
Ashwagandha's withanolides appear to modulate both the stress-cortisol axis and testosterone levels during training, two hormones that directly influence muscle protein synthesis, recovery speed, and adaptation to training load. Separately, its antioxidant and anti-inflammatory properties reduce the oxidative stress and inflammatory cytokines generated by heavy resistance training, which can limit recovery time between sessions. The VO2max effect is thought to involve improved mitochondrial function and hemodynamics.
▪ The research
What the evidence says
A randomized, double-blind, placebo-controlled trial in 57 men undergoing 8 weeks of resistance training found that those receiving ashwagandha extract (300mg twice daily) had significantly greater increases in bench press and leg extension 1RM, significantly greater gains in arm and thigh muscle size, and significantly lower serum creatine kinase (a marker of muscle damage) compared with placebo. A separate meta-analysis of ashwagandha trials in athletic populations found a mean increase in VO2max of approximately 4 ml/min/kg.
Wankhede S et al. J Int Soc Sports Nutr. 2015;12(1):43. PMID: 26609282. (Also: Bonilla DA et al., VO2max meta-analysis, JFMK. 2021;6(1):20.)
started
completed
noticed a change
made it routine
▪ What to look for
A practical buying guide
The resistance training trial used KSM-66, the same standardized form used in the stress and sleep trials. The performance effects compound across weeks of consistent training, not a pre-workout acute boost like caffeine.
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▪ What to expect over time
The main resistance training trial ran 8 weeks, and strength and muscle-size differences between groups were measured at that endpoint. Consistent training throughout is required, the supplement works by enhancing adaptation to training, not replacing it.
Side effects
Generally very well tolerated. Mild GI upset, headache.
Who should be cautious
Avoid in pregnancy. Avoid with thyroid medication without medical oversight. Use caution with hormonal therapies given the testosterone effects observed. Avoid with autoimmune conditions without clinician guidance. Always consult a care provider when adding or removing a supplement from your routine.
FAQ
Will this work without also training hard?
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Educational only. This is not medical advice. Always talk with a qualified clinician before changing medications, supplements, or care plans.