Encyclopedia · botanical
Ashwagandha
A herbal root that lowers measured stress in short trials, with one small hair study and rare reports of serious liver injury.
What it is
Ashwagandha is a root used in Ayurvedic medicine and sold as a supplement for stress. It is sometimes added to hair-supplement blends because stress is a suspected driver of shedding.
How it works
It is claimed to be an adaptogen. What has been measured is a fall in cortisol, the main stress hormone, in stressed people. A direct effect on the hair follicle has not been shown.
What the studies show
- A 2026 randomized trial gave 300 mg twice daily or placebo for 75 days to adults with hair or skin concerns. The ashwagandha group had better TrichoScan density, growth and anagen/telogen ratio. It is a single short trial without independent replication. Jillella 2026
- A systematic review of 9 studies found short-term supplementation lowered cortisol in stressed people. Long-term and adrenal effects were not studied. Della Porta 2023
- A 2025 review of herbal hair remedies lists ashwagandha among herbs with suggested benefit, and calls the evidence limited. Ahmed 2025
How it's used in studies
The hair trial used 300 mg of root extract twice daily for 75 days.
Side effects and safety
A case series of 8 people with liver injury from single-ingredient ashwagandha described cholestatic hepatitis. Three people with existing liver disease developed acute-on-chronic liver failure and died. Philips 2023 Serious injury is rare, but avoid it with liver disease, and stop if you notice yellow skin or eyes, dark urine or abdominal pain. Avoid it in pregnancy and breastfeeding.
Bottom line
One small trial is not enough to take it for months for hair. If stress-related shedding is your suspect, start with stress, sleep and hair. Discuss with a doctor.
Studies 4
Jillella A et al. A Prospective, Randomized, Double-Blind, Placebo-Controlled Clinical Study of Efficacy and Safety of Ashwagandha Root Extract Capsule on Skin and Hair Health in Healthy Adults. 2026
Tested: ashwagandha root extract 300 mg twice daily vs placebo
Result: Better TrichoScan density, growth and anagen/telogen ratio vs placebo; single short trial, no independent replication.
Read the study ↗Della Porta M et al. Effects of Withania somnifera on Cortisol Levels in Stressed Human Subjects: A Systematic Review. 2023
Tested: Withania somnifera
Result: Short-term supplementation reduced cortisol; long-term and adrenal effects not studied.
Read the study ↗Ahmed A et al. Herbal remedies for hair loss: a review of efficacy and safety. Skin Appendage Disord. 2025
Tested: herbal hair-loss remedies including amla and onion juice
Result: Names amla and onion juice among remedies backed by small, short studies.
Read the study ↗Philips CA et al. Ashwagandha-induced liver injury-A case series from India and literature review. 2023
Tested: single-ingredient ashwagandha
Result: Cholestatic hepatitis; 3 people with existing liver disease developed acute-on-chronic liver failure and died.
Read the study ↗Related
- FenugreekA seed used in traditional hair oils and masks with no human hair-growth trial behind it.
- Hair supplement blends (Nutrafol, Viviscal and similar)Branded multi-ingredient hair vitamins that beat placebo in small, mostly company-linked trials.
- Stress, sleep and hairMajor stress can trigger temporary shedding, while everyday stress and poor sleep are weaker, mostly associational links.