A 503A pharmacy is a state-licensed pharmacy that compounds medications for an individual patient on a prescription. A 503B outsourcing facility is registered with the FDA, makes sterile products in larger batches under current Good Manufacturing Practice (cGMP), and can supply licensed providers with office-use stock, subject to state law.
What is a 503A compounding pharmacy?
Section 503A of the Federal Food, Drug, and Cosmetic Act covers traditional compounding. A licensed pharmacist or physician prepares a medication for an identified patient based on a valid prescription. Oversight comes mainly from the state board of pharmacy, and these pharmacies generally follow the USP standards for compounding. 503A pharmacies are the usual choice when a patient needs a customized formulation.
What is a 503B outsourcing facility?
A 503B outsourcing facility is a compounding facility that has registered with the FDA under section 503B. It can compound sterile products with or without patient-specific prescriptions, must follow current Good Manufacturing Practice (cGMP), is inspected by the FDA on a risk-based schedule, and reports the products it makes to the FDA. Its labels identify products as compounded drugs. Because it can make larger batches, a 503B facility is commonly used to supply clinics with ready-to-use stock, where state law allows.
503A vs 503B side by side
| 503A pharmacy | 503B outsourcing facility | |
|---|---|---|
| Licensed or registered | State-licensed pharmacy | Registered with the FDA |
| Prescription | Patient-specific prescription | Can supply office-use stock without a patient-specific prescription, subject to state rules |
| Oversight | State board of pharmacy | FDA registration and inspection |
| Quality standard | USP compounding standards | Current Good Manufacturing Practice (cGMP) |
| Typical use in a clinic | Customized formulations for a named patient | Standard injectables and IV nutrients kept on hand |
Which should a clinic use?
Most practices need both. A 503B facility fits the products you use every day and keep in stock. A 503A pharmacy fits the patient who needs something prepared specifically for them. Working through a consortium that includes both means one account and one process for either route, under your own medical license.
What neither type is
Compounded drugs, including those made by 503B outsourcing facilities, are not FDA-approved. The FDA does not review them for safety, effectiveness or quality before they reach patients. Both 503A and 503B pharmacies must also follow the rules on which ingredients may be compounded, so not every product is available from every pharmacy. For the official rules, see the FDA's pages on the provisions that apply to human drug compounding and outsourcing facility registration.