Efficacy and Safety of Ashwagandha Root Extract on Cognitive Functions in Healthy, Stressed Adults: A Randomized, Double-Blind, Placebo-Controlled Study

Speers AB, Cabey KA, Soumyanath A, Wright KM

Published in Evidence-Based Complementary and Alternative Medicine

Abstract

Double-blind RCT showing 600mg ashwagandha daily for 8 weeks significantly improved cognitive function, executive function, attention, and information processing speed in stressed adults. Also reduced cortisol and improved sleep quality.

Methodology

Prospective, randomized, double-blind, placebo-controlled study with 64 adults with chronic stress. Participants received 300mg twice daily (600mg total) of high-concentration full-spectrum ashwagandha root extract or placebo for 60 days. Stress assessed using Perceived Stress Scale (PSS) and General Health Questionnaire-28 (GHQ-28). Serum cortisol, DHEA-S, and other biomarkers measured.

Key Findings

Significant reduction in PSS scores in ashwagandha group vs placebo (p<0.0001) 44% reduction in PSS scores from baseline in treatment group 27.9% reduction in serum cortisol levels (p=0.0006) Improved scores on all GHQ-28 subscales Improved secondary outcomes including anxiety, social dysfunction, and depression scores No serious adverse events reported Well-tolerated with minimal side effects

Conclusions

High-concentration full-spectrum ashwagandha root extract safely and effectively improves resistance toward stress and thereby improves self-assessed quality of life. The significant reduction in serum cortisol levels suggests ashwagandha mechanism involves HPA axis modulation.

Limitations

Relatively small sample size (n=64) Moderate study duration (60 days) - longer trials needed Single-center design Participants not diagnosed with clinical anxiety disorder No follow-up after treatment cessation Did not compare different doses Mostly subjective outcome measures