503A vs 503B Pharmacies
The two legal categories of compounding — per-patient pharmacies versus FDA-registered outsourcing facilities.
Section 503A covers traditional compounding: a pharmacy preparing medication for a specific patient's prescription, regulated primarily by its state board, exempt from FDA approval requirements but bound to USP standards. Section 503B created "outsourcing facilities" after the 2012 meningitis tragedy: volume producers who register with the FDA, follow full manufacturing-grade practices (CGMP), and submit to federal inspection.
Neither pathway makes a compounded drug FDA-approved — approval belongs to specific manufactured products — but the distinction grades oversight: 503B facilities operate closer to manufacturer discipline. For patients considering compounded GLP-1s, asking which category the dispensing pharmacy occupies is a legitimate, answerable question, and a program's willingness to answer it is itself diagnostic.
This glossary entry is general information, not medical advice, and is written to be consistent with FDA prescribing information and primary trial publications as of its last review. Always consult a licensed healthcare provider for personal medical decisions.
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