What Is Ashwagandha?

Ashwagandha (Withania somnifera) is an adaptogenic herb used in Ayurvedic medicine for over 3,000 years. Its name means "smell of the horse" in Sanskrit — referring both to its distinct odor and its traditional use for imparting vitality and strength.

Adaptogens are natural substances that help your body adapt to stress and maintain homeostasis.

Evidence-Based Benefits

Stress and Cortisol Reduction
This is where ashwagandha has the strongest evidence. A 2019 meta-analysis of 21 studies found that ashwagandha supplementation significantly reduced cortisol levels (by 15–30%) and perceived stress scores. A 2021 double-blind RCT found that 300 mg of ashwagandha extract reduced morning cortisol by 23% after 60 days.

Sleep Quality
Multiple studies show ashwagandha improves sleep quality, sleep efficiency, and time to fall asleep. The effects are most pronounced in people with insomnia and those who report high stress.

Testosterone and Fertility in Men
A systematic review found ashwagandha increases testosterone by 10–20% and sperm count and motility significantly. The effects are stronger in men with infertility or low-normal testosterone.

Physical Performance
Studies report improvements in VO2 max, muscle strength, and recovery in both athletes and sedentary individuals.

Cognitive Function
Ashwagandha improves reaction time, task performance, and working memory — likely through its effects on cortisol and GABA signaling.

Recommended Dosage

• Standard extract (withanolides standardized): 300–600 mg per day
• Root powder: 1,000–3,000 mg per day
• Duration: Cycles of 3–6 months followed by a 2-week break are common
• Timing: Most people take it in the morning (energy) or evening (sleep) — effects vary by individual

Safety and Side Effects

Ashwagandha is generally well-tolerated. Mild side effects include digestive upset, drowsiness, and headache. It is contraindicated during pregnancy and for people with hyperthyroidism or autoimmune conditions without medical supervision.

The Takeaway

Ashwagandha is one of the most researched adaptogens with solid evidence for stress reduction, sleep improvement, and hormonal support. Use a standardized extract (2.5–5% withanolides) at 300–600 mg daily for best results.