Approaches to Authenticating Products Containing Red Yeast Rice Extract (Monacolin K)

Red yeast rice (RYR) food supplements are widely used for cholesterol management owing to their content of monacolin K (MK), which, in its lactone form, is chemically identical to the prescription statin lovastatin. Despite their popularity, RYR products raise significant quality and safety concerns related to pronounced variability in MK content, frequent labeling non-compliance, contaminations with undeclared pharmaceutical statins, etc. The analytical differentiation between naturally produced MK and added synthetic lovastatin remains particularly challenging due to their identical chemical structures. This review provides a comprehensive overview of the chemical composition of RYR, with emphasis on monacolins, pigments, and relevant secondary metabolites, and critically summarizes current regulatory, safety, and quality issues associated with RYR-based food supplements. Furthermore, a practical, multi-level analytical strategy for product authentication is proposed. The approach integrates targeted quantification of MK and accompanying monacolins, identification of characteristic Monascus pigments as authenticity markers, gas chromatography-mass spectrometry for the detection of undeclared statins and other non-declared constituents, and proton nuclear magnetic resonance for global compositional fingerprinting. By combining complementary targeted and non-targeted techniques, this workflow enables more reliable authentication, detection of adulteration, and comprehensive quality assessment. The implementation of standardized analytical protocols is essential to improve transparency and enhance consumer safety in the rapidly expanding RYR supplement market.