Ashwagandha for stress, sleep and brain outcomes
What it found
In people, ashwagandha improved sleep quality and showed some benefits for stress and anxiety, but the evidence varies by product and dose.
Most other findings come from lab tests and animals.
What they found
Studies in people
Sleep quality in people
A meta-analysis of five randomized controlled trials involving 400 participants found that ashwagandha significantly improved overall sleep quality compared to a placebo. People with insomnia experienced greater improvements, and benefits were stronger with higher doses (at least 600 mg per day) and longer use (at least 8 weeks).
Stress and anxiety in people
Clinical trials and meta-analyses suggest benefits on stress- and sleep-related outcomes, but results vary because of differences in extracts, doses and populations. A recent randomized controlled trial observed reductions in stress, anxiety and a change in cortisol levels.
Testosterone in adults
Ashwagandha supplementation can raise testosterone in adults by regulating the hypothalamic-pituitary-adrenal axis and by reducing inflammation and oxidative stress, according to the paper.
Animal and lab studies
Brain effects in lab and animals
In lab tests and animal models, ashwagandha extracts and compounds reduced neuroinflammation, protected neurons and enhanced synaptic plasticity. In a mouse model of frontotemporal lobar degeneration, withaferin A alleviated TDP-43 pathology and improved cognitive function.
Antioxidant and anti-inflammatory activity
In lab tests, ashwagandha root extracts showed antioxidant effects and reduced inflammatory cytokines in cell lines. These effects are linked to activation of the Nrf2 pathway and inhibition of NF-kB signaling.
Studies in people and animals
Safety and side effects
Short-term clinical trials generally reported mild and transient side effects like stomach discomfort, nausea or drowsiness. Some cases of liver injury have been reported for certain products, often resolving after stopping. Long-term safety beyond 3 months is not well studied.
What the authors conclude
“Further well-designed, adequately powered clinical trials using standardized preparations are needed to clarify efficacy, mechanisms of action, and long-term safety.”
Also in their conclusions
- They conclude that ashwagandha shows signals of benefit for some brain-related outcomes, especially stress and sleep, but clinical evidence varies depending on the condition, extract standardization, dose and study design.
- They advise that standardized extracts are crucial in nutraceutical formulations to ensure adequate levels of bioactive compounds.
- They call for further well-designed, long-term clinical trials using standardized preparations to clarify efficacy, mechanisms and safety.
How it was done
The authors wanted to critically evaluate the scientific evidence for ashwagandha's claimed effects and highlight the strengths and limitations of the plant for use in supplements.
They searched PubMed and Scopus for studies published between 2015 and 2026 on ashwagandha, focusing on brain-related outcomes, extract standardization, dosage and safety. They prioritized human clinical trials, systematic reviews and well-characterized lab and animal studies.
What it can’t tell you
- Many findings come from lab tests and animals, which cannot show what happens in people.
- The review cannot determine long-term safety beyond 3 months, and results may not apply to all commercial products because extracts vary widely.
- It cannot confirm whether ashwagandha works for conditions like autism or addiction, as clinical evidence is limited.
Who paid
- Funding
- Funded by Solgar Multinutrients (from the PubMed record).
- Conflicts
- G.C., E.B., M.C. and P.S. are employees of Solgar Italia Multinutrient S.p.A., which also funded this work. The authors declare that this affiliation did not influence the design, interpretation, or reporting of the results. The funder had no role in the study design; collection, analysis, or interpretation of data; writing of the manuscript; or the decision to publish the results.
- Authors work at
- Madan Bhandari University of Science and Technology, Nepal; CiST College, Nepal; University of Padova, Italy
The paper
- Title
- Nutraceutical Applications of Withania somnifera : The Scientific Knowledge for Rational Modern Use of the "Ayurvedic Adaptogen"
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Licence
- CC BY. Words in quotation marks are the authors’; the rest is our summary.
- Cite
- Pandey S, Pant P, Corbioli G, et al (2026). Nutraceutical Applications of Withania somnifera : The Scientific Knowledge for Rational Modern Use of the "Ayurvedic Adaptogen". Foods (Basel, Switzerland). doi:10.3390/foods15122192Free full textPubMed 42354160DOI
Summary written 29 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error