A Comparison of British and US Pharmacopoeia Standards for Quality of Ashwagandha Dietary Supplements in Commerce

Authors: AVULA, BHARATHI - University Of Mississippi; KATRAGUNTA, KUMAR - University Of Mississippi; TATAPUDI, KIRAN - University Of Mississippi; WANG, YAN-HONG - University Of Mississippi; CHITTIBOYINA, AMAR - University Of Mississippi; KHAN, IKHLAS - University Of Mississippi

Submitted to: Phytotherapy Research
Publication Type: Review Article
Publication Acceptance Date: 12/3/2025
Publication Date: 12/12/2025
Citation: Avula, B., Katragunta, K., Tatapudi, K. K., Wang, Y. H., Chittiboyina, A. G., & Khan, I. A. (2025). A comparison of British and US Pharmacopoeia standards for quality of Ashwagandha dietary supplements in commerce. Phytotherapy Research, 0, 1–12. https://doi.org/10.1002/ptr.70148
DOI: https://doi.org/10.1002/ptr.70148

Interpretive Summary: Pharmacopoeias play a crucial role in ensuring the quality and safety of botanical raw materials by providing authoritative standards and analytical methodologies. The commercial use of aerial parts for standardization, despite traditional root-only use and phytochemical disparities, raises concerns about quality and safety. Rigorous source verification and re-evaluation of the applicability of suggested analytical methods become necessary. By utilizing morphologically verified samples, we successfully differentiated root extracts from aerial extracts, establishing a dependable metric for distinguishing Ashwagandha plant parts. To address these challenges, we developed a comprehensive method utilizing BP and USP standards to quantify three steroidal lactones in Ashwagandha plant samples, commercial extracts, and dietary supplements. Based on the USP and BP limits for standardized extracts, 44% of the products failed both BP and USP testing, while 40% passed both pharmacopeial methods. Additionally, 16% passed only the BP method. However, the USP and BP chromatographic methods were designed only for root powder and/or root extract analysis. These methods must be improved to handle a blend of leaf and root as multiple dietary supplement labels indicated a combination of these parts. Developing robust analytical tools is essential to ensure the overall quality and accurately determine the plant parts used in current Ashwagandha formulations. Such efforts are not merely about quality and authenticity, but they are critical for addressing ongoing global safety concerns related to these widely consumed supplements.

Technical Abstract: Pharmacopoeias are fundamental for ensuring the authenticity and overall quality of botanical raw materials; however, their applicability faces limits due to their inability to adapt to rapid innovation in dietary supplement products. The challenges largely stem from different standards (e.g., British Pharmacopoeia (BP) and United States Pharmacopoeia (USP), and others) and a critical lack of investigated comparisons for globally sourced materials used in botanical dietary supplements. The post-COVID surge in adaptogens, such as ashwagandha, underscores the urgency of these issues. The commercial use of aerial parts for standardization, despite traditional root-only use and phytochemical disparities, raises concerns about quality and safety. Rigorous source verification and re-evaluation of the applicability of suggested analytical methods become necessary. To address these challenges, we developed a comprehensive HPLC-UV method utilizing BP and USP standards to quantify three steroidal lactones (withaferin A, withanolide A, and withanoside IV) in Ashwagandha plant samples, commercial extracts, and dietary supplements. Our analysis revealed substantial variations in withanolide concentrations. Over 44% of products failed to meet BP standards, and 60% failed to meet USP standards. The high failure rate was attributed to high concentrations of dihydrowithaferin sulfate, primarily found in leaf samples, and the underestimation of withanolide A content. Only 10 of 25 products met both standards, and only two were confirmed as root-derived; the rest contained varying proportions of (un)disclosed aerial parts. These findings underscore critical plant-part-specific chemical variations and the need for enhanced source verification and improved quality control in the global Ashwagandha supply chain. Developing robust analytical methods and revising the existing pharmacopeial guidelines are crucial for assessing the quality and safety of Ashwagandha products, including novel formulations.