Ashwagandha: Benefits, Dosage and Side Effects

Ashwagandha works primarily by modulating the hypothalamic-pituitary-adrenal (HPA) axis. The withanolides (active compounds) bind to GABA receptors, reduce cortisol synthesis at the adrenal cortex, and dampen the body's stress response. Secondary mechanisms include thyroid hormone modulation and increased nitric oxide production.

• Stress & anxiety: Multiple double-blind RCTs show 25–30% reductions in self-reported stress vs placebo at 600 mg/day.
• Sleep quality: Improves sleep onset latency and total sleep time in adults with insomnia.
• Strength: Resistance-trained men taking 600 mg/day showed greater bench press and leg extension gains than placebo over 8 weeks.
• Testosterone: Modest increases (10–14%) in serum testosterone in men with low baseline levels.

Over 80 published human trials, including ~25 RCTs. Evidence is strongest for stress/anxiety reduction (Lopresti 2019; Salve 2019) and sleep quality (Langade 2021). Strength evidence is moderate (Wankhede 2015). Testosterone evidence is preliminary and dose-dependent.

The standardised range is 300–600 mg/day of a root extract such as KSM-66 or Sensoril. Doses up to 1,000 mg/day have been studied for short periods (<12 weeks). Take with food to reduce GI upset.

Generally well tolerated. Possible: mild GI upset, drowsiness, lower blood pressure. Rare: liver enzyme elevations (case reports).

May potentiate sedatives and thyroid medication. Caution with immunosuppressants, anti-diabetic drugs, and blood pressure medications. Avoid in pregnancy.