What is Ashwagandha?
Ashwagandha (Withania somnifera) is a shrub whose root has centuries of use in Ayurvedic practice. Modern supplements use standardized root extracts — KSM-66 and Sensoril are the most studied branded forms — typically measured by withanolide content. It is classed as an adaptogen in marketing language, a term that describes a traditional concept rather than an established pharmacological category.
How it is used in supplements
Supplement marketing positions ashwagandha for stress, anxiety-adjacent calm, sleep quality, energy, athletic recovery and testosterone support. It appears both as a standalone product and as a supporting ingredient in sleep, nerve-calm and male-vitality blends.
What the research shows
Stress is where the evidence is most consistent: several randomized trials of standardized extracts report meaningfully lower perceived-stress scores and cortisol versus placebo over 8 weeks, though studies are small and mostly conducted in India by groups with industry ties. Sleep trials show modest improvements in sleep quality and onset. Testosterone findings are limited to small studies in specific populations and do not support broad claims. Long-term data beyond a few months is essentially absent.
Typical studied amounts
Most positive trials used 240–600 mg per day of standardized root extract (commonly 5% withanolides or the KSM-66/Sensoril specifications), usually split into one or two doses. Multi-ingredient blends frequently contain far less than studied amounts without disclosing it.
Safety and side effects
Generally well tolerated over trial durations, with GI upset and drowsiness the most common complaints. A genuine caution has emerged: national pharmacovigilance systems have documented rare cases of liver injury associated with ashwagandha products, typically resolving after discontinuation. It can also modestly raise thyroid hormone levels — relevant for anyone with thyroid disease.
Medication interactions
May add to sedatives, thyroid medication, immunosuppressants and blood-pressure or blood-sugar drugs. Anyone on prescription medication should clear it with a pharmacist, and it should be stopped well before surgery.
Who should be cautious
Avoid in pregnancy — ashwagandha has documented traditional use as an abortifacient at high doses. People with autoimmune conditions, thyroid disease, hormone-sensitive conditions or liver disease should not use it without medical guidance.
References
- Ashwagandha: Usefulness and Safety. NCCIH. https://www.nccih.nih.gov/health/ashwagandha Accessed August 7, 2026.
- Ashwagandha — Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Ashwagandha-HealthProfessional/ Accessed August 7, 2026.
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