Ashwagandha for athletes: the evidence and the cautions

What it is

Ashwagandha (Withania somnifera) is a shrub whose root has been used in Ayurvedic practice for centuries. It is usually described as an adaptogen, a loose term for plants thought to help the body handle stress. Most modern trials use standardised root extracts, so a raw powder and an extract are not interchangeable.

Stress

In an eight-week trial of 60 stressed but healthy adults, ashwagandha root extract at 250 mg or 600 mg a day lowered perceived stress scores and serum cortisol, and participants reported better sleep quality than with placebo.¹ Several similar trials point the same way. Most are small and last eight weeks or less.

Sleep

A 2021 meta-analysis pooled five randomised trials with 400 adults. Ashwagandha produced a small but significant improvement in overall sleep, with larger effects in people with poor sleep, at 600 mg a day or more, and over eight weeks or longer.² The authors noted that the safety data were limited.

Strength and fitness

A 2021 systematic review of 13 studies found ashwagandha was more effective than placebo for measures of strength and power, cardiorespiratory fitness and fatigue and recovery in healthy men and women.³ Two of the authors disclosed industry ties, and the review itself called for more studies in trained athletes.

Safety, and who should avoid it

The NIH Office of Dietary Supplements says ashwagandha appears safe for up to three months, that longer-term safety is unclear, and that it might cause liver problems and affect the thyroid.⁴ The NIH's LiverTox database describes liver injury as rare, usually mild and reversible, but with severe cases reported.⁵

• Avoid it during pregnancy and breastfeeding.
• Speak to a doctor first if you have liver or thyroid conditions or take medication.
• Stop and seek advice if you notice signs such as yellowing of the skin or eyes, dark urine or unusual tiredness.

If you are tested

Ashwagandha is not on the WADA Prohibited List. The risk for tested athletes is contamination in supplements generally. Many athletes look for products certified by independent programmes that screen for banned substances, and apply the same standard to everything they take.

In practice

• Give it time. Trials ran for weeks, not nights.
• Look for a standardised root extract with the amount stated.
• Evening use fits the sleep findings, alongside magnesium and L-theanine.

A note on the studies above: they tested set amounts of a single ingredient over weeks. A shot is not a study protocol, and we do not claim that SOLACE or CALM reproduces these results.