Ashwagandha: What the Research Shows
Disclosure: This article contains links to Prolean Wellness products marked as sponsored. | FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. Products are not intended to diagnose, treat, cure, or prevent any disease. This article is for general educational purposes only and is not medical advice. Always consult your healthcare provider before starting any new supplement.
The Adaptogen With the Most Human Clinical Data
Ashwagandha (Withania somnifera) is an Ayurvedic herb that has been used in Indian traditional medicine for over 3,000 years. In Western wellness culture it is frequently described as an "adaptogen" — a class of botanical substances believed to help the body adapt to stress. What distinguishes ashwagandha from many other adaptogens is that it now has a meaningful body of randomized controlled trials in humans, not just traditional use and preclinical data.
The research is concentrated on three areas: general stress and relaxation, cortisol modulation, and sleep quality. Here is what researchers have found, with the caveat that none of this establishes that a supplement treats any diagnosed medical condition.
What Is Ashwagandha?
Ashwagandha is a small shrub native to India, North Africa, and the Mediterranean. The root extract is the primary supplemental form used in clinical research. Two proprietary standardized extracts dominate the research literature: KSM-66 (an aqueous root-only extract) and Sensoril (a root-and-leaf blend with higher withanolide content). KSM-66 has the most extensive human trial data for stress, cortisol, and performance outcomes.
The primary bioactive compounds are withanolides — steroidal lactones that appear to interact with the hypothalamic-pituitary-adrenal (HPA) axis, which governs the body's stress response. Ashwagandha is also believed to influence GABA receptor activity and thyroid hormone levels, though these mechanisms are less well established in humans.
What Researchers Are Studying
Stress and Relaxation
A 2025 systematic review and meta-analysis published in the BJPsych Open analyzed 15 randomized controlled trials with a combined 873 participants examining ashwagandha's effects on self-reported stress and anxiety measures in adults. The meta-analysis reported reductions in stress and anxiety scores in the ashwagandha groups compared to placebo, with a favorable safety profile across studies. (PMC12242034)
A well-cited 2019 double-blind, randomized, placebo-controlled trial published in Medicine administered 600 mg/day of KSM-66 ashwagandha root extract to 60 adults who reported chronic stress, for 60 days. The ashwagandha group showed a decrease in serum cortisol levels and reductions in perceived stress scores, sleep quality measures, and general wellbeing measures compared to placebo.
Sleep Quality
Multiple trials have examined ashwagandha's effect on self-reported sleep measures. A randomized, double-blind, placebo-controlled study (Langade et al.) found that 600 mg/day of ashwagandha root extract was associated with improved sleep onset latency, total sleep time, and sleep efficiency compared to placebo in adults who reported poor sleep quality, as measured by sleep actigraphy and validated questionnaires. This reflects outcomes in a specific study population — it is not a claim that ashwagandha diagnoses, treats, or cures insomnia or any other sleep disorder.
A 2023 randomized, double-blind, placebo-controlled study published in Medicine (Baltimore) found that a standardized ashwagandha root extract reduced self-reported stress and anxiety measures and improved quality-of-life scores in healthy adults over 8 weeks. (PMID: 39348746)
Cognitive Function
A 2024 double-blind, randomized, placebo-controlled study found that 600 mg/day of KSM-66 ashwagandha for 8 weeks was associated with improvements on tests of episodic memory, working memory, executive function, and attention accuracy, along with mood measures, compared to placebo in adults. Published in the Journal of Psychoactive Drugs.
What the Evidence Does NOT Show
Ashwagandha is not appropriate for everyone. Denmark banned ashwagandha supplements in 2023 citing concerns about potential thyroid and liver effects at high doses. While serious adverse events have been rare in clinical trials, case reports of liver injury associated with ashwagandha supplementation exist in the literature. Anyone with thyroid conditions or liver disease should consult their physician before use. Pregnant women should avoid ashwagandha as it may stimulate uterine contractions. None of the research above establishes that ashwagandha treats, cures, or prevents any diagnosed medical condition, including anxiety disorders or insomnia.
Who Takes Ashwagandha
Adults dealing with everyday stress or occasional difficulty winding down at night are the most common users. Ashwagandha is also popular among athletes for recovery support — several trials have shown positive effects on VO2 max and muscle strength when combined with resistance training. Adults in demanding professional environments who want general stress-management support are another common group. Anyone with a diagnosed anxiety disorder, sleep disorder, or other medical condition should talk to a healthcare provider rather than relying on a supplement alone.
★ Sponsored — Prolean Wellness Product
Ashwagandha — Prolean Wellness
Our Ashwagandha supplement uses a standardized root extract as part of a balanced daily wellness routine.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
How to Take Ashwagandha
Most clinical trials use 300–600 mg/day of a standardized extract, taken once or twice daily. KSM-66 at 600 mg/day is the most studied protocol in the research summarized above. It can be taken with or without food, though taking it with a meal may reduce the risk of mild gastrointestinal upset. Always follow the suggested use on your specific product label or your healthcare professional's guidance.
Most clinical trials measured outcomes at 8–12 weeks of consistent use.
The Bottom Line
Ashwagandha has a relatively large human clinical research base compared to many other adaptogens, with a 2025 meta-analysis of 15 RCTs reporting effects on self-reported stress and anxiety measures. Findings on cortisol and sleep quality are also notable but should be treated as general background rather than a promise of individual results, and none of it substitutes for evaluation and care from a healthcare provider for a diagnosed condition. Quality and individual response vary.
References
1. Bachour G, et al. Effects of ashwagandha on cortisol, stress and anxiety: systematic review and meta-analysis of 15 RCTs. BJPsych Open. 2025. PMC12242034
2. Majeed M, et al. Standardized ashwagandha root extract alleviates stress and anxiety in healthy adults. Medicine (Baltimore). 2023. PMID: 39348746
3. Chandrasekhar K, et al. Prospective, randomized double-blind, placebo-controlled study of KSM-66. Indian J Psychol Med. 2012. PMID: 23439798
FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. Products mentioned are not intended to diagnose, treat, cure, or prevent any disease. This article is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before beginning any supplement regimen.