Ashwagandha (KSM-66)

Key points

• KSM-66 is the most clinically studied extract — root-only, 5% withanolides, standardised dose
• Reduces cortisol by 15–30% in RCTs over 8 weeks — measurable stress hormone reduction
• Improves sleep quality by reducing physiological arousal — distinct from sedation
• Do not use long-term without cycling — Huberman recommends 2–3 months on, 1 month off
• 300–600mg of KSM-66 is the studied range; take at night when cortisol is naturally lowest