Artificial sweeteners (ASs) and dyes are widely used in foods, beverages and pharmaceutical and are recognized as emerging environmental contaminants due to their persistence and widespread occurrence. These substances often pass through the human body unchanged and resist wastewater treatment processes, leading to continuous introduction into aquatic environments and potential long-lasting term environmental effects. This study investigated, for the first time, the biodegradability of nine commercial dietary supplements, both natural and those containing ASs and synthetic dyes, using the Organisation for Economic Cooperation and Development (OECD) 301 F ready biodegradation test (RBT), which is a respirometry-manometric method. While the products showed good biodegradability, those containing ASs and dyes were further studied to determine their fate at the end of the RBT. The study involved developing and validating a chromatographic method to quantitatively determine the presence of Acesulfame K (1), Sucralose (2), Tartrazine (3) and Carmoisine (4) in the RBT mineral medium, using ultra-high performance liquid chromatography (UHPLC) coupled with two detectors: a high-resolution mass-spectrometer with quadrupole time-of-flight (qToF) and a UV-Vis diode array detector (DAD). Results indicated that these additives were not readily biodegraded, highlighting a potential significant environmental concern. This issue extends beyond dietary supplements to all Pharmaceutical and Personal Care Products (PPCP) including drugs and medical devices. The findings underscore the importance of raising cultural awareness about the environmental impact of persistent substances, encouraging the healthcare chain and patients to make informed choices. From a One Health perspective, reducing environmental contamination can lead to positive outcomes for human health.