What are adaptogens — do they actually work for cortisol?

Adaptogens are plant-derived compounds claimed to normalize stress response by modulating the HPA axis, of the clinically studied adaptogens, ashwagandha (Withania somnifera) has the strongest evidence for reducing cortisol in stressed adults (mean reduction of approximately 27% in one RCT vs. placebo), while rhodiola rosea has evidence for reducing perceived stress and cortisol-related fatigue, and other adaptogens (reishi, eleuthero, schisandra) have insufficient human trial data to support specific cortisol claims (Chandrasekhar et al., Indian J Psychol Med, 2012).

The Chandrasekhar 2012 trial showing ashwagandha reduced cortisol by 27% is frequently cited. What is less frequently mentioned: the population was "chronically stressed adults" (not men with normal stress load), the dose was KSM-66 ashwagandha root extract at 300 mg twice daily, and the follow-up was 60 days. Generalizability to all men is limited. The effect size is real but modest relative to the effect of the cortisol drivers being addressed, if you are sleeping 5.5 hours a night and working 70-hour weeks, no adaptogen will meaningfully shift your cortisol burden.

Honesty Scale: Ashwagandha for cortisol in stressed populations, Promising (2). Rhodiola for perceived stress and fatigue, Promising (2). Adaptogens as a substitute for addressing the structural causes of elevated cortisol, Unsupported (5).

What to do: Ashwagandha KSM-66 at 300 mg twice daily is reasonable to add as a supportive intervention once you are also addressing sleep, stress load, and exercise. Do not take it as a substitute for those structural changes.

For the full picture, read The Cortisol Rhythm Deep Dive