Heavy Metal Contamination in Adaptogenic Herbal Dietary Supplements: Experimental, Assessment and Regulatory Safety Perspectives

While adaptogens are popular in dietary supplements for their health-promoting properties, their safety is compromised by the risk of heavy metal contamination, a threat amplified by inconsistent regulatory standards. This study aimed to assess the extent of heavy metal contamination in adaptogenic supplements on the Polish market and evaluate their compliance with international safety limits. Eleven commercially available supplements (tablets, powders, dried materials) containing Withania somnifera, Rhodiola rosea, Panax ginseng, and Schisandra chinensis were analyzed for lead (Pb), cadmium (Cd), mercury (Hg), nickel (Ni), and other elements using flame atomic absorption spectroscopy (FAAS) and mercury analysis (AMA 254). Results demonstrated widespread contamination, primarily with Pb and Ni. In processed forms (tablets and dried fruits), Pb concentrations exceeded permissible limits by up to 235%, while Ni levels were exceeded by up to 321%. Schisandra chinensis preparations showed the highest contamination levels. Furthermore, raw materials from India contained significantly higher Ni concentrations than those from China (p < 0.01). These findings reveal that a majority of the tested supplements fail to meet toxicological safety criteria, posing a significant health risk to consumers. This underscores a critical regulatory gap and highlights the urgent need for harmonized standards and stringent quality control for dietary supplements.