Ashwagandha
Ashwagandha is an adaptogen that lowers serum cortisol. In the most-cited study, cortisol fell by around 28 percent after 60 days at twice 300 mg, against 8 percent in the placebo group. Meta-analyses confirm that effect and are divided on whether perceived stress also measurably drops.
What the research shows
Shown, with a clear condition or a limited scope.
Three independent meta-analyses are available. Li (2026) pools thirteen randomised studies with 599 participants and finds an average effect of 0.47 on performance, where the prediction interval crosses zero and only aerobic endurance comes out consistently. Pérez-Gómez (2020) sees a higher VO2max based on four studies with 142 participants and wide scatter. Arumugam (2024) finds lower stress scores and lower cortisol across nine studies with 558 participants. The underlying trials are small and the extract often comes from the manufacturer: in Chandrasekhar (2012) Ixoreal Biomed supplied the KSM-66 extract. An effect that exists while being small and unevenly spread lands on reasonable.
Who it makes sense for: Best supported for people dealing with stress and mediocre recovery, at 600 mg of standardised root extract per day over several weeks. For an acute lift just before training it is the wrong tool, because the effect builds over weeks. Stay away from it with thyroid conditions, during pregnancy and breastfeeding, and while on immunosuppressive medication.
How we weigh evidenceClinical dosage
Origin
NaturalAshwagandha (Withania somnifera) is a plant from the Ayurvedic tradition used for over 3000 years. The root is dried and extracted. KSM-66 is the most studied extract.
Safety
Well tolerated at 600 mg per day, the dose used in both key studies. Do not use during pregnancy or with thyroid conditions without consulting a doctor. The extract in the cortisol study was supplied by Ixoreal Biomed, owner of KSM-66, while the study reports no conflict of interest.
For comparison
Ashwagandha is comparable to ginseng in Chinese medicine. It's not a 'strange chemical' but a plant as common in India as chamomile is in Europe.
Dosage by weight and gender
The effective ashwagandha dose is 300-600mg standardized extract (e.g. KSM-66) per day (Wankhede et al., 2015). Body weight does not play a major role in dosing. Women and men benefit similarly, but women should avoid it during pregnancy due to potential effects on the uterus. Ashwagandha can raise thyroid hormones, so consult your doctor first if you have thyroid issues.
Frequently asked questions
What is ashwagandha?
Ashwagandha is an herbal extract from Ayurvedic medicine. It's an adaptogen that helps your body manage stress by lowering the stress hormone cortisol. It can also improve muscle mass and strength.
Is ashwagandha dangerous?
At normal doses (300-600mg/day) ashwagandha is safe for most people. Avoid it during pregnancy and with thyroid conditions without consulting your doctor. For long-term use (beyond 3 months), it's best to cycle with breaks.
How much ashwagandha per day?
Take 300-600mg standardized extract (KSM-66 or Sensoril) per day. You can take it morning or evening. The effect builds up over 2-4 weeks of daily use.
Scientific sources
The clinical dosages on this page are based on peer-reviewed research.
- Effects of Ashwagandha (Withania Somnifera) on stress and anxiety: A systematic review and meta-analysisArumugam V et al. (2024)
- A prospective, randomized double-blind, placebo-controlled study of safety and efficacy of a high-concentration full-spectrum extract of ashwagandha root in reducing stress and anxiety in adultsChandrasekhar K et al. (2012)Funded by: Opgegeven financiering: geen. Het KSM-66-extract werd geleverd door Ixoreal Biomed. Auteurs verklaren geen belangenverstrengeling.
- Effects of Withania somnifera (Ashwagandha) Supplementation on Exercise Performance: A Systematic Review and Three-Level Meta-AnalysisLi X et al. (2026)Funded by: National Education Science Planning Foundation of China. Auteurs verklaren geen belangenverstrengeling.
- Effects of Ashwagandha (Withania somnifera) on VO(2max): A Systematic Review and Meta-AnalysisPérez-Gómez J et al. (2020)Funded by: Auteurs verklaren geen belangenverstrengeling.
Pre-workouts with Ashwagandha
No products found with this ingredient
We keep the dosages and values on this page as accurate as possible based on selected studies. New research may change these values. Nothing on this page is medical advice. If you have any doubts, always consult a doctor.