A pharmacy that prepares customized medications tailored to individual patient needs, as opposed to dispensing mass-manufactured drugs. Compounding pharmacies operate under two distinct regulatory frameworks defined by the Drug Quality and Security Act (DQSA) of 2013.

503A pharmacies compound medications based on individual prescriptions, typically in small quantities. 503B outsourcing facilities can produce larger batches without patient-specific prescriptions but must register with the FDA and comply with current good manufacturing practice (CGMP) requirements. The distinction matters enormously in the peptide space: compounds like semaglutide and tirzepatide have been available from compounding pharmacies during FDA-declared drug shortages, but this access depends on the compound’s shortage status and the specific regulatory framework governing each pharmacy type.