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Ashwagandha

Reviewed by the Nimbera editorial team · Last updated May 2026

A 16-week double-blind, placebo-controlled crossover RCT (PMC6438434, n=57) found ashwagandha supplementation produced a 14.7% greater increase in testosterone compared to placebo (p=0.010). NCCIH confirms limited evidence that ashwagandha for 2-4 months may increase testosterone and sperm quality.$20-$40 per month

How to use

Take 300-600 mg of standardised ashwagandha root extract (KSM-66 or Sensoril, standardised to 5% withanolides) once or twice daily with meals. Allow at least 8 weeks to assess effects. Take continuously, as benefits appear to require ongoing use.

How it works

Ashwagandha is an adaptogen that appears to reduce cortisol levels by modulating the hypothalamic-pituitary-adrenal (HPA) axis. Because chronically elevated cortisol suppresses testosterone production, lowering cortisol may allow the hypothalamic-pituitary-gonadal (HPG) axis to function more effectively. Withanolides may also directly stimulate luteinising hormone (LH) release, which signals the testes to produce testosterone.

Where to buy

KSM-66 Ashwagandha by Jarrow Formulas (iHerb, Amazon), Thorne Ashwagandha (Thorne.com, iHerb), NOW Foods Ashwagandha KSM-66 (Amazon, iHerb). Look specifically for KSM-66 or Sensoril branded extracts for standardised potency.

Typical cost: $20-$40 per month

Safety notes

Do not use if you have hormone-sensitive prostate cancer - the testosterone-raising effect may be contraindicated. May interact with thyroid medications (can alter thyroid hormone levels), immunosuppressants, sedatives, and blood pressure drugs. Can cause drowsiness, digestive upset, or diarrhoea. Avoid during pregnancy. Only confirmed safe for short-term use (up to 3 months in most studies). Stop use 2 weeks before surgery.

Drug & supplement interactions

  • Always tell your doctor or pharmacist about any supplements you take.
  • Interactions can occur with prescription medications, blood thinners, and immunosuppressants.
  • Herbal remedies can affect how the body absorbs or metabolises drugs.
  • Check drugs.com interactions checker before starting.

Clinical source

Lopresti et al., Ashwagandha raises testosterone 14.7% in RCT, PMC6438434, 2019

This information is compiled from primary clinical literature and is for informational purposes only. It is not a substitute for professional medical advice. Read our full disclaimer.