News · 2026-06-04
503A vs 503B Pharmacies: What Patients Should Know
Why the compounding pathway behind your prescription matters more than ever in 2026.
Quick Answer
503A pharmacies compound for a specific patient under a prescription; 503B outsourcing facilities compound at larger scale and are the focus of the FDA's 2026 bulks-list proposal. Knowing which one fills your prescription affects both legality and provenance.
Full explainer: 503A vs 503B. See also the glossary and a provider profile.
Bottom Line
Ask any provider which pharmacy fills your prescription and whether it is 503A or 503B.
Compounded semaglutide is not FDA-approved as a finished drug product. Compounded medications may be prescribed only when clinically appropriate and must be evaluated by a licensed prescriber. Branded medications such as Wegovy and Ozempic are FDA-approved products; compounded semaglutide is different and should not be described as FDA-approved, “generic Wegovy,” or “generic Ozempic.”