503A vs. 503B: What Clinics Should Know About Compounding Pharmacies

If your clinic works with compounded medications, you've likely seen "503A" and "503B" on pharmacy websites. The labels come from two sections of the Federal Food, Drug, and Cosmetic Act, and they describe different ways a pharmacy is allowed to compound.

503A pharmacies compound for individual patients. A 503A pharmacy prepares a medication for a specific patient, based on a valid prescription from a licensed practitioner. These pharmacies are licensed and inspected primarily by state boards of pharmacy, and sterile compounding follows USP <797> standards.

503B outsourcing facilities compound in larger batches. A 503B facility registers with the FDA, follows current Good Manufacturing Practice requirements, and can compound without a patient-specific prescription, typically for office use by healthcare facilities.

Neither produces FDA-approved drugs. Compounded medications from either type of pharmacy are not FDA-approved. They are meant to meet patient needs that commercially available products can't.

What this means for your clinic. If you prescribe for individual patients, a 503A pharmacy is built around that workflow: each order is tied to a patient and a prescriber. When you evaluate a 503A partner, ask:

• Which states is the pharmacy licensed in, and does that cover where your patients live?

• How does the pharmacy test its sterile preparations, and can it share its testing process?

• Who do you talk to when you have a question about a prescription?

ReShape Rx is a licensed 503A compounding pharmacy network. If you'd like to talk through how we work with clinics, contact our pharmacy.

​Compounded medications are not FDA-approved. They are prepared for individual patients pursuant to a valid prescription from a licensed practitioner.