What Is Cortisol and Why Does It Matter?
Cortisol is a stress hormone produced by the adrenal glands that plays a key role in the body's "fight or flight" response. In the short term, cortisol helps us focus and react, but chronically elevated cortisol is linked to numerous health issues — sleep disturbances, weight gain, weakened immune function and persistent fatigue.
Over the past decade, researchers have investigated ashwagandha (Withania somnifera) for its effects on cortisol levels, and the results have been noteworthy.
Key Clinical Trials
Chandrasekhar et al. (2012): 27.9% Cortisol Reduction
This double-blind, placebo-controlled study enrolled 64 chronically stressed adults. Participants received 300 mg of KSM-66 ashwagandha root extract twice daily (600 mg total) for 60 days.
Results:
- Serum cortisol decreased by 27.9% compared to placebo
- Perceived Stress Scale (PSS) scores improved significantly
- Adverse effects were minimal and comparable to placebo
Lopresti et al. (2019): Reduced Stress and Anxiety Scores
This trial used a lower dose — 240 mg of ashwagandha extract per day — and included 60 participants experiencing stress symptoms.
Results:
- Hamilton Anxiety Rating Scale (HAM-A) scores improved significantly
- Morning cortisol levels dropped noticeably
- Depression, Anxiety and Stress Scale (DASS-21) scores improved
Salve et al. (2019): Better Sleep Quality
In this study, 150 healthy adults received 600 mg ashwagandha extract per day for 8 weeks.
Results:
- Sleep quality improved significantly (Pittsburgh Sleep Quality Index)
- Time to fall asleep decreased
- Perceived stress levels reduced
How Does Ashwagandha Work?
Ashwagandha appears to influence the HPA axis (hypothalamic-pituitary-adrenal axis) — the body's central stress response system. Researchers believe its active compounds, particularly withanolides, modulate HPA axis function.
Mechanism overview:
| Component | Ashwagandha's Proposed Role |
|---|---|
| HPA axis | Modulates stress response |
| Cortisol | Reduction observed in clinical trials |
| GABA receptors | May influence GABAergic system |
| Oxidative stress | Antioxidant properties |
Important Context
While the trial results are promising, several limitations deserve attention:
1. EFSA has not approved health claims for ashwagandha — the findings presented are research results, not authorised health claims
2. Sample sizes are relatively small — larger-scale trials are needed for confirmation
3. Doses and extract types vary — KSM-66 is a standardised extract; results may not apply to all ashwagandha products
4. Individual variation — effects may differ from person to person
Practical Summary of the Research
Dosages used in trials:
- 240–600 mg standardised ashwagandha extract per day
- Usually split into 1–2 doses
- Trial duration: 8–12 weeks
What to look for when choosing a product:
- Standardised extract (e.g. KSM-66 or Sensoril)
- Withanolide content stated on the label
- Third-party testing
Who Might Consider Ashwagandha?
Based on the existing research, ashwagandha may be of interest to people who:
- Experience chronic stress
- Seek natural supportive options
- Want to support healthy sleep
- Are interested in adaptogens more broadly
Important: Consult a healthcare professional before starting any new supplement, especially if you take medication or have existing health conditions.
References
- Chandrasekhar, K., Kapoor, J., & Anishetty, S. (2012). A prospective, randomized double-blind, placebo-controlled study of safety and efficacy of a high-concentration full-spectrum extract of ashwagandha root in reducing stress and anxiety in adults. Indian Journal of Psychological Medicine, 34(3), 255–262.
- Lopresti, A. L., Smith, S. J., Malvi, H., & Kodgule, R. (2019). An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract. Medicine, 98(37), e17186.
- Salve, J., Pate, S., Debnath, K., & Langade, D. (2019). Adaptogenic and anxiolytic effects of ashwagandha root extract in healthy adults: A double-blind, randomized, placebo-controlled clinical study. Cureus, 11(12), e6466.
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Disclaimer
Dietary supplements are not a substitute for a varied, balanced diet and healthy lifestyle. The research findings presented do not constitute approved health claims.
