Ashwagandha: Research
Overview
This page provides a curated overview of selected peer-reviewed scientific studies examining ashwagandha (Withania somnifera), a botanical used traditionally in Ayurvedic medicine and increasingly studied in modern clinical research. The goal of this page is to provide transparent access to commonly cited research within the scientific literature. The summaries below describe findings reported in published studies and are presented for educational purposes as part of a clinician-led review of the scientific literature.
Important Context for Readers
Scientific studies examine outcomes in defined populations under specific research conditions. Results reported in individual studies may not apply to all individuals, and findings should not be interpreted as guaranteed outcomes. This page summarizes selected research examining stress resilience, sleep quality, physical performance, cognitive function, and related physiological biomarkers studied in relation to ashwagandha. It is not intended to provide medical advice, diagnosis, or treatment recommendations. This page is provided for educational purposes and does not include product recommendations or affiliate links.
Summary of Evidence
Across human clinical studies and meta-analyses, ashwagandha supplementation has been studied for its potential associations with perceived stress, cortisol regulation, sleep quality, physical performance, recovery, and selected cognitive outcomes.
While results vary across study populations, extract types, and study designs, multiple randomized controlled trials and systematic reviews have reported improvements in stress-related measures and sleep outcomes under study conditions. The studies listed below represent several frequently cited publications within the ashwagandha literature. Many studies involve relatively small sample sizes, short durations, specific populations, and symptom-based outcome measures rather than long-term clinical outcomes.
Key Areas of Research
Mechanistic and Physiological Research
Evidence strength: Low (preclinical and experimental data).
1) Lopresti AL, Smith SJ, Malvi H, et al. An Investigation into the Stress-Relieving and Pharmacological Actions of an Ashwagandha Extract. Medicine. 2019.
PMID: 31517876
DOI: https://doi.org/10.1097/MD.0000000000017186
Population: Adults experiencing stress.
Design: Randomized, double-blind, placebo-controlled clinical study evaluating a standardized ashwagandha extract over 8 weeks.
Key Findings:
• Significant improvements reported in perceived stress measures.
• Cortisol concentrations decreased relative to placebo.
• Findings support potential modulation of hypothalamic-pituitary-adrenal (HPA) axis activity.
Stress and Anxiety Support
Evidence strength: Moderate to Strong.
Randomized trials and meta-analyses have examined the relationship between ashwagandha and measures of perceived stress, anxiety, cortisol, and psychological well-being.
2) Chandrasekhar K, Kapoor J, Anishetty S. A Prospective, Randomized Double-Blind, Placebo-Controlled Study of Safety and Efficacy of a High-Concentration Full-Spectrum Ashwagandha Root Extract in Reducing Stress and Anxiety in Adults. Indian J Psychol Med. 2012.
PMID: 23439798
DOI: https://doi.org/10.4103/0253-7176.106022
Population: Adults experiencing chronic stress (n=64).
Design: Randomized placebo-controlled trial evaluating KSM-66® 300 mg twice daily for 60 days.
Key Findings:
• Significant reductions reported in stress-assessment scores.
• Cortisol concentrations decreased relative to placebo.
• Improvements reported in measures of psychological well-being.
3) Akhgarjand C, Asoudeh F, Bagheri A, et al. Does Ashwagandha Supplementation Have a Beneficial Effect on the Management of Anxiety and Stress? A Systematic Review and Dose-Response Meta-Analysis of Randomized Controlled Trials. Phytother Res. 2022.
PMID: 36017529
DOI: https://doi.org/10.1002/ptr.7598
Population: Adults across randomized controlled trials evaluating stress and anxiety outcomes.
Design: Systematic review and dose-response meta-analysis of randomized controlled trials.
Key Findings:
• Improvements reported in both stress and anxiety outcomes across pooled analyses.
• Benefits observed across multiple extract types and study populations.
• Dose-response analyses suggested variability based on extract, dose, and study design.
4) Arumugam V, Venugopal V, Balakrishnan A, et al. Effects of Ashwagandha (Withania somnifera) on Stress and Anxiety: A Systematic Review and Meta-Analysis. Explore. 2024.
PMID: 39348746
DOI: https://doi.org/10.1016/j.explore.2024.103062
Population: Adults participating in randomized controlled trials evaluating stress and anxiety outcomes.
Design: Systematic review and meta-analysis.
Key Findings:
• Improvements reported in subjective measures of stress and anxiety.
• Favorable changes reported in several stress-related biomarkers.
• Overall findings supported further investigation of standardized ashwagandha extracts.
Sleep Quality
Evidence strength: Moderate to Strong.
Several randomized trials and pooled analyses have evaluated sleep quality, sleep efficiency, sleep onset, and related sleep outcomes.
5) Cheah KL, Norhayati MN, Yaacob LH, et al. Effect of Ashwagandha (Withania somnifera) Extract on Sleep: A Systematic Review and Meta-Analysis. PLoS One. 2021.
PMID: 34559859
DOI: https://doi.org/10.1371/journal.pone.0257843
Population: Adults across randomized controlled trials evaluating sleep outcomes.
Design: Systematic review and meta-analysis.
Key Findings:
• Improvements reported in overall sleep quality measures.
• Benefits appeared greatest among individuals with insomnia or elevated stress.
• Sleep efficiency and sleep onset measures improved in several studies.
• Extracts providing approximately 600 mg daily for at least 8 weeks appeared most consistently associated with benefit.
6) Langade D, Kanchi S, Salve J, et al. Efficacy and Safety of Ashwagandha Root Extract in Insomnia and Anxiety: A Double-Blind, Randomized, Placebo-Controlled Study. Cureus. 2019.
PMID: 31728244
DOI: https://doi.org/10.7759/cureus.5797
Population: Adults with insomnia and anxiety.
Design: Randomized placebo-controlled trial.
Key Findings:
• Improvements reported in sleep quality.
• Sleep onset latency improved under study conditions.
• Improvements observed in anxiety-related measures.
Physical Performance and Recovery
Evidence strength: Moderate.
Several randomized trials and pooled analyses have evaluated ashwagandha supplementation in healthy adults participating in exercise programs.
7) Wankhede S, Langade D, Joshi K, et al. Examining the Effect of Withania somnifera Supplementation on Muscle Strength and Recovery. J Int Soc Sports Nutr. 2015.
PMID: 26609282
DOI: https://doi.org/10.1186/s12970-015-0104-9
Population: Healthy young men participating in resistance training (n=57).
Design: Randomized placebo-controlled trial evaluating 600 mg/day of ashwagandha root extract.
Key Findings:
• Greater increases reported in muscular strength compared with placebo.
• Improvements observed in recovery measures.
• Favorable changes reported in body composition outcomes.
8) Bonilla DA, Moreno Y, Gho C, et al. Effects of Ashwagandha (Withania somnifera) on Physical Performance: Systematic Review and Bayesian Meta-Analysis. J Funct Morphol Kinesiol. 2021.
PMID: 33670194
DOI: https://doi.org/10.3390/jfmk6010020
Population: Adults participating in exercise and performance studies.
Design: Systematic review and Bayesian meta-analysis.
Key Findings:
• Improvements reported in selected measures of muscular strength.
• Improvements reported in cardiorespiratory fitness outcomes.
• Findings suggested potential benefits across several physical performance domains under study conditions.
Neuropsychiatric and Cognitive Outcomes
Evidence strength: Moderate.
Emerging research has examined cognition, mood, attention, and executive function.
9) Choudhary D, Bhattacharyya S, Bose S. Efficacy and Safety of Ashwagandha (Withania somnifera (L.) Dunal) Root Extract in Improving Memory and Cognitive Functions. J Diet Suppl. 2017.
PMID: 28471731
DOI: https://doi.org/10.1080/19390211.2017.1284970
Population: Adults with mild cognitive impairment (n=50).
Design: Randomized, double-blind, placebo-controlled clinical trial evaluating standardized ashwagandha root extract over 8 weeks.
Key Findings:
• Improvements reported in immediate and general memory measures compared with placebo.
• Improvements observed in executive function, attention, and information-processing speed.
• Findings suggested potential benefits for selected cognitive outcomes under study conditions.
10) Ng QX, Loke W, Foo NX, et al. A systematic review of the clinical use of Withania somnifera (Ashwagandha) to ameliorate cognitive dysfunction. Phytotherapy Research. 2019
PMID: 31742775
DOI: https://doi.org/10.1002/ptr.6552
Population: Adults across clinical studies evaluating cognitive dysfunction, memory, attention, executive function, and related neuropsychological outcomes.
Design: Systematic review of human clinical studies examining the effects of ashwagandha supplementation on cognitive function.
Key Findings:
• Several studies reported improvements in memory, executive function, attention, and reaction time under study conditions.
• Included populations varied and included older adults with mild cognitive impairment and adults with neuropsychiatric conditions.
• Authors concluded that early clinical evidence supports further investigation, while larger and longer-duration randomized trials are still needed.
Safety and Tolerability
Evidence Strength: Moderate.
11) Raut AA, Rege NN, Tadvi FM, et al. Exploratory Study to Evaluate Tolerability, Safety, and Activity of Ashwagandha in Healthy Volunteers. J Ayurveda Integr Med. 2012.
PMID: 23125505
DOI: https://doi.org/10.4103/0975-9476.100168
Population: Healthy volunteers.
Design: Prospective safety and tolerability study.
Key Findings:
• Ashwagandha was generally well tolerated.
• Reported adverse events were primarily mild.
• Findings supported further clinical investigation.
12) Helgi K. Björnsson, Einar S. Björnsson, Bharathi Avula, et al. Ashwagandha-induced liver injury: A case series from Iceland and the US Drug-Induced Liver Injury Network. Liver International. 2020.
PMID: 31991029
DOI: https://doi.org/10.1111/liv.14393
Population: Five adults with suspected ashwagandha-associated liver injury identified in Iceland and through the U.S. Drug-Induced Liver Injury Network (DILIN).
Design: Case series evaluating the clinical presentation and outcomes of suspected ashwagandha-induced liver injury after exclusion of alternative causes and structured causality assessment.
Key Findings:
• Five cases of liver injury attributed to ashwagandha-containing supplements were identified.
• Liver injury typically presented as a cholestatic or mixed pattern with jaundice and pruritus.
• Symptom onset generally occurred within several weeks of initiating supplementation.
• All patients recovered following discontinuation, with normalization of liver tests occurring over approximately 1–5 months.
• Findings suggest that clinically apparent liver injury associated with ashwagandha is possible but appears uncommon relative to widespread use.
Educational Notice
These summaries are provided for educational purposes to review published scientific literature and should not be interpreted as medical advice, diagnosis, or treatment recommendations. Readers should consult qualified healthcare professionals for personal medical decisions.
FDA Disclaimer
These statements have not been evaluated by the U.S. Food and Drug Administration. Dietary supplements are not intended to diagnose, treat, cure, or prevent any disease.
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