Individually Recognized Functional Ingredients of Korean Health Functional Foods: Functional Classification, Regulatory Context, and Clinical Implication

Background/Objectives: The global health functional food (HFF) market is expanding rapidly, driven by increasing consumer interest in preventive healthcare and evidence-based nutrition. The Republic of Korea has established a systematic regulatory framework for HFFs, through the Individually Recognized Functional Ingredient (IRFI) system introduced in 2004. Designed to accommodate innovative physiologically active ingredients beyond standardized categories, the IRFI system is increasingly discussed as a regulatory model for evidence-based functional foods. This study examines the IRFI system within a comparative regulatory context and evaluates its implications for drug–dietary supplement interactions (DDSIs). Methods: Functional categories were defined according to guidelines issued by the Ministry of Food and Drug Safety (MFDS). Data on Korean IRFIs were obtained from the Food Safety Korea database. A literature search was conducted in PubMed using regulatory keywords which identified through Google searches. Regulatory frameworks in the United States, European Union, Japan, and China were comparatively analyzed. DDSIs were reviewed based on MFDS-approved IRFIs and the relevant literature. Results: The IRFI represents a hybrid regulatory model that combines rigorous pre-market scientific evaluation, including GLP-compliant safety testing and human clinical evidence, with regulatory incentives such as expedited review and temporary market exclusivity. Compared with post-market-oriented systems in the United States and Japan, the stringent authorization framework in the European Union, and the dual-track health food system in Chinese, IRFI integrates clinical evidence requirements within a structured pre-market approval process. Conclusions: The IRFI framework establishes a comparatively stringent evidentiary standard for functional foods while providing a structured basis for evaluating potential DDSIs. Its applicability depends on alignment and mutual recognition of scientific and clinical evaluation criteria across regulatory jurisdictions. DDSIs were reviewed based on MFDS-approved IRFIs and the relevant literature.