A conversation with Mr. Adam Marcus, co-founder of Retraction Watch and editor for Primary Care at Medscape

Clinicians increasingly encounter patients using or requesting peptide-based therapies sourced through compounding pharmacies. The U.S. Food and Drug Administration has identified a subset of bulk drug substances, including certain peptides, that may present significant safety risks when used in compounded formulations. The clinical question is whether these regulatory signals reflect meaningful patient-level risk and how they should influence prescribing behavior. This matters because compounded peptides often sit outside traditional approval pathways, creating uncertainty around quality, dosing consistency, and safety. Understanding...