Withania somnifera · herb
Evidence tier: moderate
Reduces cortisol, builds stress resilience, and supports energy and mood
Ashwagandha acts mainly on the nervous system and the endocrine system. Its withanolides are thought to calm the body's stress response pathway, the HPA axis, which is the leading explanation for its effect on stress. Leading explanation, not a proven mechanism.
Moderate evidence for everyday stress, and nothing stronger. NCCIH, the US National Center for Complementary and Integrative Health, says some ashwagandha preparations may help with stress and sleep while the evidence for anxiety on its own is unclear. Systematic reviews do not agree with each other: a 2024 review found only limited evidence for anxiety and insomnia (PMID 39083548), a 2022 review found conflicting trial results (PMID 36017529), and more recent meta analyses report a measurable drop in stress and anxiety (PMID 41644067, PMID 39348746). It is a real and fairly well studied stress ingredient, held back by small trials and many different product forms. For male testosterone and sperm quality the evidence is limited (two to four months of use, per NCCIH). For cognition, athletic performance, menopause and blood sugar there is not enough evidence to say anything. Safety carries a signal the seed missed: NIH LiverTox rates ashwagandha a likelihood score B, a likely cause of clinically apparent liver injury, usually appearing two to twelve weeks after starting, and says to avoid it in cirrhosis or advanced liver disease.
150 to 600 mg of extract, one to three times daily, often standardised to withanolide content. Best taken with food. NCCIH considers it possibly safe for short use, up to about three months.
Take it daily with food; the effect on stress builds over weeks, not in one dose. Use a set course of up to about 3 months, then review, because NCCIH's safety window is about 3 months and LiverTox reports liver injury usually appearing 2 to 12 weeks after starting. Stop and see a doctor if skin or eyes turn yellow, urine darkens or there is unusual tiredness. Stop before planned surgery. Not for pregnancy, breastfeeding, autoimmune or thyroid conditions, or hormone sensitive prostate cancer (NCCIH).
Onset: ~28 days
Well tolerated at standard doses; generally recognized as safe by WHO. Contraindicated in pregnancy due to withanolide induced uterine contractions. Long term safety (>12 months) not extensively studied. May cause mild GI upset in sensitive individuals.
Pregnancy: avoid
Breastfeeding: avoid
A cornerstone of Ayurvedic medicine for over 3,000 years, classified as a Rasayana, a rejuvenating tonic for longevity and vitality. Used in traditional Indian medicine for stress, insomnia, and physical stamina. One of the most researched adaptogens in modern botanical science.
Active compounds: withanolides
Remedies using Ashwagandha · Browse by body system · Check it against what you take
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.