Mexican dietary supplements commonly contain toxic heavy metals like lead, arsenic, and chromium. While individual metal levels in most supplements appeared safe when consumed alone, the cumulative exposure from multiple metals could increase cancer risk over a lifetime. The study found that some popular supplements, particularly those marketed for weight loss and blood detoxification, contained concerning metal levels, especially seaweed-based products and animal-origin supplements. Better regulation and labeling of dietary supplements in Mexico is urgently needed to protect consumers from long-term health risks.