Ashwagandha

Does it work?

• -A little. The strongest, most consistent evidence is for stress, anxiety, and sleep — root extract reliably lowers perceived stress and cortisol in trials. It also nudges strength and muscle gains during a training block, but those effects are small and the studies are short and industry-heavy. Useful if stress or poor sleep is wrecking your recovery; not a serious strength supplement on its own.

How much · when

• -300-600 mg/day of a standardized root extract (e.g. KSM-66 or Sensoril), the doses used in most trials.
• -Take it daily and consistently — effects build over 4-8 weeks, not from a single dose.
• -Splitting into two doses (morning and evening) or taking it at night is common; with food helps if it upsets your stomach.
• -Treat it as a stress/sleep aid that supports recovery — not as a pre-workout or a substitute for protein and progressive overload.

The catch

• -Strength and muscle gains in the trials are real but small, and the studies are short (8-12 weeks), often funded by extract makers, and use varied formulas — so the effect is likely overstated.
• -Most of the 'gains' benefit may be indirect: better sleep and lower stress let you train and recover harder, rather than a direct anabolic action.

Safety

• -Rare but real case reports of idiosyncratic liver injury exist (per NIH LiverTox); stop and see a doctor if you get nausea, dark urine, or yellowing skin, and avoid it if you have liver disease.
• -Can affect thyroid hormone levels and may add to sedatives — check with your doctor if you take thyroid or sleep/anxiety medication.
• -Avoid in pregnancy and breastfeeding; quality and actual dose vary a lot between brands, so choose a standardized, third-party-tested extract.

Key research

• Effects of Ashwagandha (Withania somnifera) on Physical Performance: Systematic Review and Bayesian Meta-AnalysisJ Funct Morphol Kinesiol · 2021 · Meta-analysis
• Effects of Ashwagandha (Withania somnifera) on VO2max: A Systematic Review and Meta-AnalysisNutrients · 2020 · Meta-analysis
• Dual impact of Ashwagandha: Significant cortisol reduction but no effects on perceived stress - A systematic review and meta-analysisNutr Health · 2025 · Meta-analysis
• Effects of Ashwagandha Supplements on Cortisol, Stress, and Anxiety Levels in Adults: A Systematic Review and Meta-AnalysisBJPsych Open · 2025 · Meta-analysis
• Examining the effect of Withania somnifera supplementation on muscle strength and recovery: a randomized controlled trialJ Int Soc Sports Nutr · 2015 · RCT

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