Ashwagandha
Adaptogenic herb traditionally used in Ayurvedic practice.
Also known as KSM-66, Sensoril, Withania somnifera
Common doses
300-600 mg
Best timing
Evening
Food
Take with food
Interactions
6 known
Ashwagandha (Withania somnifera) is an adaptogenic herb used in Ayurvedic medicine for over 3,000 years. It is classified as an adaptogen because it helps the body resist physical and mental stress by modulating the HPA (hypothalamic-pituitary-adrenal) axis, which controls the cortisol stress response.
Modern research on ashwagandha has been surprisingly robust for an herbal supplement. Multiple randomised controlled trials show significant reductions in cortisol levels, perceived stress, and anxiety. It also appears to support testosterone levels in men, improve exercise performance, and enhance sleep quality.
The root extract is the most commonly studied part of the plant. Branded extracts like KSM-66 and Sensoril are standardised for withanolide content and have the most clinical evidence behind them. The typical dose is 300-600 mg of root extract daily.
Key benefits
Stress and cortisol
Multiple RCTs show ashwagandha reduces serum cortisol by 11-32% and significantly reduces perceived stress and anxiety scores.
Sleep quality
Ashwagandha may support sleep quality, particularly the onset and depth of sleep. Studies show improvements in sleep quality scores at 300-600 mg daily.
Exercise performance
Some studies show modest improvements in VO2 max, strength, and recovery time in trained and untrained individuals.
Testosterone
Several studies show increased testosterone levels in men, particularly in stressed or subfertile populations. The mechanism may be partly through cortisol reduction.
Available forms
KSM-66
Full-spectrum root extract standardised to 5% withanolides. The most clinically studied extract. 300-600 mg/day is typical.
Sensoril
Root and leaf extract standardised to 10% withanolides. Tends to be more calming/sedating. 125-250 mg/day is typical.
Generic Root Powder
Unstandardised whole root powder. Cheaper but less potent and less predictable. Typically dosed at 1-3 grams daily.
Upper intake limit
No established upper limit. Studies have used up to 1,200 mg/day of root extract without serious adverse effects. May affect thyroid hormone levels; people with thyroid conditions should consult a doctor.
Research summary
Good evidence for stress reduction and cortisol modulation (multiple RCTs). Moderate evidence for sleep, testosterone, and exercise performance. Emerging evidence for cognitive function. Important: ashwagandha may influence thyroid hormones (T3, T4, TSH), so people with thyroid conditions or on thyroid medication should use with medical guidance.
Known interactions (6)
Both promote relaxation — additive sedation possible
Two sedatives with overlapping mechanisms
Complementary calm through different pathways
Two adaptogens with complementary stress pathways
A traditional Ayurvedic pairing for cognition and stress
Complementary hormonal support through different mechanisms
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1 flagZinc and Iron compete for the same absorption pathway. Take at least 2 hours apart.
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This information is for educational purposes only. It is not medical advice and does not diagnose, treat, cure, or prevent any disease. Always consult a qualified healthcare professional.