Evidence overview
Ashwagandha
Ashwagandha (Withania somnifera) is the most-researched adaptogenic herb in modern supplement science, with a clinical literature concentrated heavily on anxiety, stress, and sleep, plus secondary research streams in strength, testosterone, and cognitive function. The evidence has reached practice-guideline status for anxiety in the World Federation of Societies of Biological Psychiatry / Canadian Network for Mood and Anxiety Treatments framework, which is unusual for an herbal supplement.
Most studied for
Coverage pending
PubMed coverage
Coverage pending
Safety profile
In your full report
Mechanism class
Adaptogenic herb from the nightshade family used in Ayurvedic medicine for centuries. Active constituents...
Study coverage
Study coverage by goal
PubMed counts for Ashwagandha grouped by the goal each study targets.
Evidence overview is temporarily unavailable for Ashwagandha.
Evidence
What the evidence covers
The terrain of the published literature, not its conclusions.
Ashwagandha (Withania somnifera) is the most-researched adaptogenic herb in the supplement literature, with clinical research concentrated on anxiety and stress (the dominant use), sleep quality, athletic performance and strength, testosterone and male reproductive health, and cognitive function. The herb has been used in Ayurvedic medicine for centuries; modern supplement research uses standardized root extracts, most commonly KSM-66 and Sensoril (two patented extracts that dominate the trial literature). Active constituents include withanolides, steroidal lactones whose mechanisms are still being characterized in modern pharmacology.
The outcome dimensions covered most heavily are anxiety and stress (the supplement's primary established use, anchored by a 2022 WFSBP/CANMAT clinician-guidelines document), sleep quality (a rapidly growing literature with multiple recent meta-analyses), strength and athletic performance, testosterone and male fertility markers (smaller and more contested), and general cognitive function. Cortisol modulation is a consistently-measured biomarker across many of these outcomes; the supplement has well-documented short-term effects on serum cortisol, which is the mechanistic basis often cited across indications.
Demographically, the literature concentrates on healthy adults under stress (the dominant trial population), with substantial subsamples in clinical anxiety, athletic populations, and males with fertility concerns. Specific extract differences (KSM-66 vs. Sensoril vs. generic standardized) is a methodologically important question that the field is still working through; head-to-head comparisons are thinner than the market implies. Trial duration is typically 6-12 weeks, which is shorter than would be ideal for establishing long-term safety and durability of effects.
Safety
Safety summary
Common adverse events, drug interactions, and special populations.
Ashwagandha is generally well-tolerated in short-to-medium-term trials (typically up to 12 weeks). The most-common adverse effects are mild gastrointestinal discomfort, drowsiness, and headache. Concerns have been raised in the recent literature about possible liver-injury cases, particularly with concentrated extracts; the European Food Safety Authority and several national regulators have issued cautionary statements about ashwagandha-associated hepatotoxicity, though the absolute risk appears low and the mechanism remains unclear. Drug interactions include theoretical additivity with sedatives and immunosuppressants, and the herb is generally contraindicated in pregnancy (possible abortifacient effects reported in traditional and preclinical sources). People with autoimmune conditions, hyperthyroidism, or who are pregnant should consult a clinician before use.
This summary is informational and not medical advice. Consult a clinician before starting or changing any supplement, especially if you take prescription medications.
Foundations
Foundation of the evidence base
A few studies the field anchors on. Not the full picture, just the starting points.
Expert-society consensus document from the World Federation of Societies of Biological Psychiatry and Canadian Network for Mood and Anxiety Treatments that assesses ashwagandha's efficacy for anxiety disorders. The field's clearest practice-guideline-level positioning of ashwagandha, which is unusual for an herbal supplement.
View on PubMedWidely-cited systematic review and meta-analysis on ashwagandha's effects in anxiety and stress - the supplement's primary established use. Provides the field's evidence synthesis that informs the WFSBP/CANMAT guideline position.
View on PubMed
Limitations
What this page doesn't answer
Where the public summary stops and the personalized report begins.
This page summarizes the ashwagandha literature at a general level. It does not address which extract (KSM-66, Sensoril, or generic standardized) is right for your specific goal, what dose has been shown effective in trials matching your demographic, the appropriate duration of use (most evidence is from 6-12 week trials), or how ashwagandha interacts with the medications, supplements, and conditions you have. The recent regulatory caution about hepatotoxicity in some markets adds an additional layer of decision-making that benefits from personalized framing rather than population-level summary.
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