Clinical Evaluation of Ashwagandha in Stress and Anxiety Disorders

Abstract

Ashwagandha (Withania somnifera) has been used in Ayurveda for centuries as a rasayana for what modern practice would call chronic stress and anxiety. Modern clinical interest has grown in parallel, but the evidence base is uneven: small trials, varying extracts, different dose schedules, and outcome measures that rarely line up. In this 12-week, randomised, double-blind, placebo-controlled clinical evaluation, we compared four groups of adults with moderate stress and anxiety (n = 240 overall; 60 per arm): placebo, Ashwagandha root extract 300 mg twice daily, Ashwagandha root extract 600 mg twice daily, and Ashwagandha 600 mg twice daily combined with a structured yoga-nidra protocol. Participants were recruited from four European clinical integrative-medicine centres. Primary outcome was change in Hamilton Anxiety Rating Scale (HAM-A). Secondary outcomes included the Perceived Stress Scale (PSS-10), morning serum cortisol, Pittsburgh Sleep Quality Index (PSQI), serum DHEA-S, and treatment-emergent adverse events. We scored overall clinical benefit using the Ashwagandha Clinical Efficacy Index (ACEI), a weighted composite of anxiety reduction, stress reduction, cortisol normalisation, sleep improvement, and tolerability. ACEI values were 0.921 in the 600 mg + yoga arm and 0.862 in the 600 mg arm, versus 0.718 (300 mg) and 0.344 (placebo). HAM-A fell by 58.4% from baseline in the 600 mg + yoga arm and by 52.2% in the 600 mg arm. Morning cortisol dropped by 28.6% in the 600 mg + yoga arm. Adverse events were mild and comparable across arms. Findings support standardised Ashwagandha root extract at 600 mg twice daily as a well-tolerated intervention for moderate stress and anxiety, with additional benefit when paired with a structured mind-body protocol.