Medical food (US) and FSMP (EU)

Medical foods operate in a distinct regulatory category from dietary supplements. US framework under 21 CFR 101.9(j)(8) and Section 5(b) of the Orphan Drug Act uses a four-criteria test: enteral consumption only (not parenteral), distinctive nutritional requirements established by medical evaluation that cannot be met by normal diet modification, disease-specific formulation with documented nutritional rationale, and use under medical supervision with physician-directed regimen. EU Regulation 609/2013 with Delegated Regulation 2016/128 establishes Food for Special Medical Purposes (FSMP) with notification to Member State competent authority, FSMP sub-categories (nutritionally complete standard, nutritionally complete nutrient-adapted, nutritionally incomplete) and prescribed FSMP labelling. Inborn errors of metabolism drive the most distinctive formulations — PKU phenylalanine-restricted protein substitutes, MSUD branched-chain amino acid-restricted, urea cycle protein-restricted, organic acidemia and tyrosinaemia disease-specific formulations — with specialised metabolic dietitian and metabolic physician supervision. Specialty pharmacy, hospital pharmacy and metabolic clinic pantry programmes are the appropriate distribution channels rather than retail or open e-commerce. The supplement-vs-medical-food positioning boundary is the dominant failure mode — 'medical-grade' supplement marketing to clinical channels and direct-to-consumer e-commerce of true medical foods both undermine the framework distinctions and trigger FDA Warning Letter and EU Member State enforcement.