Abstract Selective androgen receptor modulators (SARMs), including andarine (S-4), have gained significant attention in the dietary supplement market despite their known health risks and prohibition in competitive sports. Although andarine remains widely available, data on its actual presence in dietary supplements are limited. To address this gap, this study assessed the quality of dietary supplements marketed as containing andarine. An HPLC–HRMS method was developed, validated, and applied to analyze three commercially available dietary supplements. HRMS (QTOF) detection, in MS as well as MS/MS regimes, was essential for confirming the presence of andarine and unexpectedly identifying other biologically active substances, specifically the metabolic modulators SR9009 and GW501516, based on precise molecular weights of precursor and product ions relative to reference standards. The analysis revealed discrepancies between the labeled and actual contents of the analyzed dietary supplements. These findings underscore the potential health risks posed by mislabeled and adulterated dietary supplements and highlight the urgent need for stricter quality control and regulatory oversight in the dietary supplement industry.
Slíz et al. (Thu,) studied this question.