Ashwagandha
Research Reliability -
An adaptogenic root studied for the stress response. Trials report lower cortisol and better sleep quality in some participants, though results vary widely between individuals.
Appetite
Mood
Sleep
Ashwagandha
Description
Ashwagandha (Withania somnifera) is one of the most extensively researched adaptogenic herbs, with a centuries-long history of use in Ayurvedic medicine. It modulates the HPA axis to lower chronically elevated cortisol, which can otherwise impair sleep, suppress immune function, reduce testosterone, and contribute to anxiety. Clinical trials show significant reductions in perceived stress, cortisol levels, and symptoms of anxiety with consistent use. It also improves sleep quality, supports thyroid function, and may increase testosterone and endurance in men. A foundational adaptogen for anyone managing high stress.
Effects
First week
a subtle take-the-edge-off calm for some
Weeks 2–4
Ongoing
How It Feels
The effect is a gradual smoothing of stress rather than an on-off feeling; over a few weeks the same pressures bother you less. Some people feel pleasantly calm, a few feel flat or emotionally muted, which is the cue to lower the dose. Take with food to avoid mild stomach upset.
Evidence
Evidence Strength
Moderate (some human RCTs)
Caveats
Most robust trials used the specific branded KSM-66 extract at studied doses; generic ashwagandha products may not match this evidence base. Avoid in pregnancy and with certain thyroid or autoimmune conditions without medical guidance.
Usage
Commonly Referenced Starting Amount
300 mg/day standardized root extract
Commonly Referenced Amount
300–600 mg/day standardized extract (commonly KSM-66) is the range used in most stress and cortisol research
Referenced Upper Limit
No formal upper limit has been established; a 12-week trial at 2,000 mg/day found no clinically significant liver, kidney, or thyroid changes, though rare case reports of liver injury exist at various doses. Contraindicated in pregnancy, and it can shift thyroid hormone levels
Onset
2–4 weeks (stress/cortisol)
Biomarkers to Track
Subjective
(Daily)
Stress and anxiety score (1–10)
Energy and fatigue levels
Sleep quality score
Objective
(Quarterly)
Salivary cortisol (AM and PM)
Testosterone (males, quarterly)
Thyroid TSH and free T3/T4
Generally safe but it raises thyroid hormone and there are rare reports of liver injury.
Pregnant women, people with hyperthyroidism or autoimmune thyroid disease, and those on thyroid or sedative medication.
Taking it forever without breaks, and ignoring feeling flat or emotionally muted as a cue to lower the dose.
Disclaimer
This information is for educational purposes only and is not medical advice. It is not intended to diagnose, treat, cure, or prevent any disease. Consult a qualified healthcare provider before starting any new supplement, especially if you are pregnant, nursing, taking medication, or managing a health condition.
Chandrasekhar K et al. (2012). Indian Journal of Psychological Medicine. RCT (KSM-66 ashwagandha and stress/cortisol). PMID: 23439798. DOI: 10.4103/0253-7176.106022.
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