A multicentre clinical trial involving 1,200 adults has found no evidence of treatment-related liver or kidney injury among participants who received a standardized Ashwagandha root extract daily for 24 weeks.
The study, published in Frontiers in Medicine on August 20, 2026, evaluated the prolonged use and tolerability of Ashwagandha following COVISHIELD vaccination.
The randomised, double-blind, placebo-controlled trial involved apparently healthy adults aged between 18 and 70 who had received a first, second or booster dose of the COVISHIELD vaccine.
Participants were randomly assigned either 500 mg of a standardized aqueous Ashwagandha root extract daily, equivalent to four grams of raw root powder, or a matching placebo. Treatment continued for 24 weeks, with participants followed until week 28. Of the 1,200 people enrolled, 1,032, or 86%, completed the study.
Researchers reported that liver and kidney function parameters remained within the study’s reference ranges during the intervention. Tests included liver enzymes, bilirubin, creatinine and blood urea, with investigators reporting no treatment-related hepatic or renal injury.
No serious adverse event was considered attributable to the intervention, while none of the participants withdrew from the trial because of an adverse event.
The study also examined whether Ashwagandha affected the immune response generated by COVISHIELD vaccination. Virus-neutralising activity remained above 85% in both the Ashwagandha and placebo groups, with researchers reporting no statistically significant difference between them.
The trial was carried out at seven sites in India by 45 researchers associated with nine institutions. These included the Central Council for Research in Ayurvedic Sciences, All India Institute of Ayurveda, National Institute of Ayurveda in Jaipur, Translational Health Science and Technology Institute and Savitribai Phule Pune University, among others. The trial was also registered with the Clinical Trials Registry-India.
Dr Arvind Chopra, lead author of the study, said the findings provided important evidence on the safety and tolerability of standardized Ashwagandha during 24 weeks of use. He also noted that the intervention did not appear to interfere with vaccine-induced immunity.
Ministry of Ayush Secretary Vaidya Rajesh Kotecha said rigorous clinical research could help strengthen the scientific evidence base for Ayurveda and encourage the responsible use of standardized interventions.
CCRAS Director General Prof Rabinarayan Acharya and National Professor of Ayush Prof Bhushan Patwardhan also underlined the importance of well-designed clinical trials in assessing traditional preparations using contemporary scientific methods.
The researchers said the findings add to clinical evidence regarding standardized Ashwagandha preparations. However, the results specifically relate to the extract, dosage, participant population and 24-week period evaluated in this trial and should not automatically be generalized to all Ashwagandha products or patterns of use.
