Large 24-Week Trial Finds Standardised Ashwagandha Root Extract Well Tolerated Without Liver or Kidney Injury

A large multicentre clinical trial involving 1,200 adults has found that a standardised Ashwagandha root extract was well tolerated over 24 weeks, with no evidence of treatment-related liver or kidney injury under the conditions studied.

The randomised, double-blind, placebo-controlled trial was published in Frontiers in Medicine on August 20, 2026. Researchers evaluated the safety, tolerability and immune-related effects of prolonged Ashwagandha administration in adults who had received COVISHIELD vaccination.

Trial Included 1,200 Adults Across Seven Indian Centres

The study enrolled 1,200 apparently healthy adults between 18 and 70 years of age who had received either the first, second or booster dose of COVISHIELD.

Participants were randomly assigned in a 1:1 ratio to receive either 500 mg of a standardised aqueous Ashwagandha root extract once daily or a matching placebo. Each 500 mg dose was equivalent to around 4 grams of Ashwagandha root powder.

The intervention continued for 24 weeks, followed by an additional four-week observation period. Of the 1,200 participants enrolled, 1,032 completed the trial, giving an overall completion rate of 86%.

The trial was conducted across seven centres in India and involved researchers from institutions working in Ayurveda, clinical medicine, rheumatology, integrative health and biomedical research.

Liver and Kidney Parameters Remained Within Reference Ranges

The study placed particular emphasis on long-term safety monitoring.

Laboratory assessments included liver enzymes, bilirubin, creatinine, blood urea and other haematological and biochemical parameters.

According to the published results, liver and kidney function parameters remained within reported reference ranges, with no treatment-related hepatic or renal injury detected during the 24-week intervention period.

No serious adverse event was considered attributable to the Ashwagandha intervention, and no participant withdrew from the trial because of an adverse event.

The adverse events that did occur were predominantly mild and gastrointestinal in nature.

Study Extends Evidence on Longer-Term Ashwagandha Use

One of the significant aspects of the trial is its duration.

Ashwagandha has been widely used in Ayurveda, but high-quality clinical evidence examining prolonged daily administration over several months has been comparatively limited.

The researchers noted that the study provides important evidence on the tolerability of standardised Ashwagandha use over 24 weeks in healthy vaccinated adults under controlled conditions.

This does not mean that every Ashwagandha preparation or every population will have an identical safety profile. The findings apply specifically to the standardised aqueous root extract, dosage and participant population evaluated in this trial.

Ashwagandha Did Not Interfere With Vaccine-Induced Immunity

The researchers also examined whether daily Ashwagandha administration affected the immune response generated by COVISHIELD vaccination.

Neutralising antibody activity remained high in both the Ashwagandha and placebo groups, and the researchers did not identify a statistically significant additional immune benefit attributable to Ashwagandha.

The study therefore found no evidence that the standardised extract interfered with vaccine-induced immunity, while also concluding that an additional humoral immune benefit could not be demonstrated.

The cumulative incidence of breakthrough SARS-CoV-2 infection in the overall study population was 3.9%.

Trial Involved Major Ayurveda and Biomedical Institutions

The research brought together 45 investigators from nine institutions, reflecting an effort to evaluate an Ayurvedic intervention using contemporary clinical-trial standards.

Participating institutions included the Central Council for Research in Ayurvedic Sciences, the All India Institute of Ayurveda, the National Institute of Ayurveda, the Translational Health Science and Technology Institute, Savitribai Phule Pune University and other research centres.

The trial was registered with the Clinical Trials Registry–India under CTRI/2021/06/034496.

Researchers Highlight Need for Evidence-Based Ayurveda

Vaidya Rajesh Kotecha, Secretary of the Ministry of Ayush, said rigorous clinical research can strengthen the scientific evidence base for standardised Ayurvedic interventions and support their responsible use.

Lead author Dr. Arvind Chopra highlighted the importance of the liver and kidney findings, noting that the trial generated controlled clinical evidence on the safety and tolerability of prolonged Ashwagandha administration.

Researchers involved in the study also stressed that well-designed clinical trials are essential for evaluating traditional formulations within modern healthcare frameworks.

Study Has Important Limits

The researchers cautioned that the results should not automatically be extended to all populations.

The study involved apparently healthy adults, and its findings may not directly apply to elderly people, immunocompromised individuals or people with significant co-morbidities.

The trial also evaluated one standardised preparation at a defined dose, meaning the findings should not be interpreted as a blanket safety guarantee for all commercial Ashwagandha products.

Clinical Evidence for Ashwagandha Continues to Strengthen

The 24-week trial adds an important piece of controlled clinical evidence to the growing scientific literature on Ashwagandha.

By demonstrating good tolerability without treatment-related liver or kidney injury in a large, randomised population, the study strengthens the evidence base for standardised Ashwagandha preparations used under defined conditions.

It also shows how Ayurvedic formulations can be studied through large, multicentre clinical trials, bringing traditional knowledge and modern research methods together in a more evidence-driven framework.

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References

Press Information Bureau, Ministry of Ayush, Government of India — “24-Week Clinical Trial Finds No Evidence of Liver or Kidney Injury with Standardised Ashwagandha Root Extract,” September 28, 2026.

Chopra A. et al. — “Safe prolonged prophylactic use and tolerability of Ashwagandha following COVISHIELD™ vaccination over 24 weeks: a multicentre randomized double-blind placebo-controlled trial,” Frontiers in Medicine, Volume 13, August 20, 2026.

Published on 20 August 2026, (Front. Med., Vol 13, 20 August 2026.https://doi.org/10.3389/fmed.2026.1852954) the study, titled “Safe prolonged prophylactic use and tolerability of Ashwagandha following COVISHIELD™ vaccination over 24 weeks: a multicentre randomised double-blind placebo-controlled trial,”

Clinical Trials Registry–India — CTRI/2021/06/034496.

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