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Ashwagandha

Also known as: Withania somnifera, Indian ginseng

An Ayurvedic herb classed as an "adaptogen", mostly studied as a root extract for stress and sleep.

Common forms: Root extract capsules (e.g. KSM-66) · Root + leaf extract (e.g. Sensoril) · Powder

Draft summary, not yet reviewed by a qualified health professional · Last updated 2026-11-03

Talk to a healthcare professional first

This information is for education only and is not medical advice, diagnosis, or treatment. Supplements can interact with medications and health conditions. Check with your doctor or pharmacist before starting anything, especially if you take medication, are pregnant or breastfeeding, or have a health condition. These statements have not been evaluated by the FDA; supplements are not intended to diagnose, treat, cure, or prevent any disease.

What the evidence says

Stress & anxious feelings

BModerate evidence

Meta-analyses of randomized trials found ashwagandha reduced perceived stress and anxiety scores and lowered cortisol versus placebo. Trials are generally small and short (6–12 weeks).

Dose used in studies
300–600 mg/day standardized root extract
Time to effect
4–8 weeks
Studies (2)

Sleep quality

BModerate evidence

A meta-analysis found a small but significant improvement in overall sleep, with larger effects in people with insomnia, at doses of 600 mg/day or more for at least 8 weeks.

Dose used in studies
600 mg/day root extract
Time to effect
≥8 weeks
Most relevant for
Adults with stress-related sleep problems
Studies (2)

Safety

Common side effects

  • Stomach upset
  • Drowsiness
  • Diarrhea

Avoid or ask your doctor first if

  • You are pregnant or trying to conceive
  • You have a thyroid condition (may raise thyroid hormone levels)
  • You have liver disease (rare cases of liver injury reported)
  • You have an autoimmune condition
  • You have surgery scheduled within 2 weeks

Pregnancy & breastfeeding

Avoid during pregnancy and breastfeeding.

Medication interactions

  • moderateThyroid medication: May increase thyroid hormone levels and alter thyroid medication needs.
  • moderateSedatives / sleep medications: May add to the effects of sedatives and sleep medications.
  • moderateImmunosuppressants: May stimulate the immune system and reduce the effect of immunosuppressants.
  • minorDiabetes medications: May lower blood sugar.
  • minorBlood pressure medications: May lower blood pressure.

This list covers common medication classes only and is not exhaustive.

Buying tips

Look for third-party testing seals (USP Verified, NSF Certified, or Informed Choice) and match the form and dose used in studies.

Where to buy (affiliate)

Further reading