Compound or practice · Supplement
Ashwagandha
The best-evidenced adaptogen for cortisol and stress — with a real question mark on long-term use.
- Overall grade
- Grade B
- Last revised
- 5
- graded outcomes
- 3
- references listed
A hand-written entry in Prometheus's bundled library. Its grades are the entry's own reading of the evidence, not a peer-reviewed review.
1 at grade A · 4 at grade B · 2 at grade C · 2 at grade D — 9 graded rows
What is known
Each outcome with its grade (how strong the evidence is, A to D), the size of the effect where the entry records one, and how often studies agree.
- Perceived stress / anxietyEvidence grade A
Consistent across 10+ RCTs in stressed adults
Moderatehigh
- Cortisol reductionEvidence grade B
~15–25% salivary cortisol vs placebo
Moderatehigh
- Sleep qualityEvidence grade B
Best in people with stress-driven insomnia
Smallmixed
- Testosterone (stressed men)Evidence grade C
Likely cortisol-mediated; absent in relaxed cohorts
Smallmixed
- Long-term safety (>6 months)Evidence grade D
Trials are short; case reports of liver stress exist
Unclearlow
Conditions
How the entry reads its effect on diagnosed conditions: the direction first, then the grade. Never a substitute for the person who treats you.
- Generalized anxiety ImprovesEvidence grade BConsistent perceived-stress and HAM-A reductions in stressed adultsGrade B
- Stress-driven insomnia ImprovesEvidence grade BSleep gains track the cortisol dropGrade B
- Subclinical hypothyroidism May improveEvidence grade CRaises T3/T4 modestly — coordinate if you take thyroid medicationGrade C
- Liver conditions May worsenEvidence grade DRare hepatotoxicity case reports; stop on symptoms and re-testGrade D
What is uncertain
Read off the same rows as above. Nothing here is added that the entry does not itself record.
- Thin evidence: Testosterone (stressed men) (grade C); Long-term safety (>6 months) (grade D).
- Studies disagree: Sleep quality (mixed agreement).
Up: % of baseline. Across: weeks. The cortisol floor drops over ~8 weeks in stressed cohorts; subjective calm lags it by a couple of weeks.
The evidence in words
What it is
A root extract (withanolides are the active class) used for stress modulation. KSM-66 and Sensoril are the standardized extracts most trials actually used — unstandardized powder is a different, weaker product.
What the evidence shows
Meta-analyses show meaningful reductions in perceived stress and cortisol (~15–25% salivary cortisol in stressed populations), moderate sleep improvements, and small testosterone bumps in stressed men (likely downstream of cortisol, not a direct androgen effect). Almost all trials are ≤12 weeks — the long-term picture is genuinely unknown, and rare case reports of liver stress and emotional blunting exist.
What to expect
2–4 weeks to feel the stress floor drop; evening HRV often rises before you notice anything subjectively. If you feel emotionally flat, stop — that's the known off-target effect, not a dosing problem.
How it is used
As the entry records it, from the studies it summarises. Not a recommendation for you — doses that suit a trial population may not suit you.
- Standard
- 600mg/day standardized extract (KSM-66), with dinner. Trials split 300mg ×2 work equally.
- Duration
- Run 8–12 week blocks with a deliberate off month — mirrors the trial windows and respects the unknown long-term profile.
Goes with
- Magnesium L-ThreonateComplementary evening mechanisms — cortisol floor + brain magnesiumEvidence grade B
Questions people ask
Emotional blunting — real?
Reported by a minority, mechanism plausible (GABAergic + cortisol floor). It reverses on stopping. Treat it as a hard stop signal.
Morning or night?
Evening fits the sedative lean; morning if it makes you drowsy is pointless — switch to rhodiola for daytime energy instead.
Related reading
Entries that share this one's tags or conditions.
- Magnolia Bark for SleepEvidence grade C — EarlyEvidence grade C
- Magnolia BarkA traditional anti-stress bark (honokiol/magnolol) with early cortisol and sleep signals.Evidence grade C
- Magnolia Bark for Stress / cortisolEvidence grade C — Often combinedEvidence grade C
- Magnolia Bark: dosage and how to take itStandardized extract, evening.Evidence grade C
Sources
As this entry records them: title, journal and year. None carries a DOI or PubMed id, so none is linked as a verified paper. Each link searches PubMed for the title; check that what you find is what the entry describes.
- 1.Ashwagandha for stress and anxiety: systematic review & meta-analysis — Phytother Res, 2022. Search PubMed (opens in a new tab)
- 2.KSM-66 and salivary cortisol in stressed adults: RCT — Indian J Psychol Med, 2012. Search PubMed (opens in a new tab)
- 3.Withania somnifera and sleep: meta-analysis — PLoS One, 2021. Search PubMed (opens in a new tab)
Last revised . A grade is this entry's reading of the evidence, not medical advice.