What Ashwagandha Is
Ashwagandha (*Withania somnifera*) is an herb used in traditional Ayurvedic practice and now sold widely as a stress and sleep supplement. Here's what the U.S. government's National Center for Complementary and Integrative Health (NCCIH) actually reports about it.
What the Evidence Shows
NCCIH's read of the research is cautious [1]:
- Stress and sleep: 'Research shows that some ashwagandha preparations may be effective for insomnia and stress.'
- Anxiety: the evidence is unclear.
- Testosterone and sperm quality: some limited evidence from 2-to-4-month use.
- Most other uses (athletic performance, cognition, menopause, and more): not enough evidence to draw conclusions.
Notice that 'some preparations' is doing real work in that sentence — products vary, and results from one standardized extract don't automatically apply to another (see Standardized Extracts Explained).
Safety: What to Know
- Liver injury: NCCIH states that 'although it is rare, there have been a number of cases that link liver injury to ashwagandha supplements' [1]. Stop use and seek care if you notice symptoms such as unusual fatigue, abdominal pain, dark urine, or yellowing of the skin or eyes.
- Pregnancy and breastfeeding: NCCIH advises that ashwagandha 'should be avoided during pregnancy and should not be used while breastfeeding' [1].
- Duration: it 'may be safe when taken in the short term (up to 3 months)'; long-term safety is not established [1].
- Common side effects: drowsiness, stomach upset, diarrhea, and vomiting.
- Thyroid and sedatives: ashwagandha may raise thyroid hormone levels and add to the effect of sedatives — talk to a clinician if you take thyroid medication or sleep aids.
Before You Take It
Tell your health care provider about ashwagandha (and any supplement), especially if you have a liver condition, take other medications, are pregnant or breastfeeding, or have an upcoming surgery (see When to Stop a Supplement Before Surgery).