How the FDA's Compounding Exemption Law Actually Works
Federal law allows pharmacy compounding under specific exemptions from standard drug approval requirements. Here's the legal structure behind that exemption.
By the GLP Semaglutide editorial team · Last updated July 8, 2026
U.S. federal law (primarily Sections 503A and 503B of the Federal Food, Drug, and Cosmetic Act) creates exemptions allowing licensed pharmacies and outsourcing facilities to compound drug products without going through the full new-drug approval process, under specific conditions.
503A vs. 503B
Section 503A generally covers traditional pharmacy compounding tied to an individual patient prescription; Section 503B covers larger-scale 'outsourcing facilities' that can compound in bulk without a patient-specific prescription, subject to different, more extensive FDA oversight requirements.
The shortage-drug provision
A specific provision allows compounding of a copy of an FDA-approved drug's active ingredient when that drug is on the FDA's shortage list — the legal basis that enabled widespread semaglutide and tirzepatide compounding during 2022–2024, and the basis that narrowed once shortages were resolved.
Primary sources