503A pharmacy vs 503B outsourcing facility
Both make compounded drugs. The law treats them differently. Last checked 5 November 2026.
| 503A: compounding pharmacy | 503B: outsourcing facility | |
|---|---|---|
| Federal law | Section 503A of the FD&C Act (21 U.S.C. 353a) | Section 503B of the FD&C Act (21 U.S.C. 353b) |
| Who compounds | A licensed pharmacist in a State-licensed pharmacy or a Federal facility, or a licensed physician. | Compounded by or under the direct supervision of a licensed pharmacist, in a facility that registers with FDA as an outsourcing facility (the statute defines one as a facility that compounds sterile drugs). |
| Prescription needed? | Yes. Compounded for an identified individual patient on a valid prescription. The statute allows limited quantities before a prescription arrives, based on a history of orders within an established relationship. | A patient-specific prescription is not required; an outsourcing facility may or may not obtain prescriptions for identified patients. A drug dispensed or distributed other than on a prescription for an identified patient must be labeled “Office Use Only.” |
| Manufacturing standard | Exempt from the federal current good manufacturing practice (cGMP) requirement in 21 U.S.C. 351(a)(2)(B) when the 503A conditions are met. | cGMP applies. |
| Bulk ingredients | Tiered conditions: a USP or NF monograph substance if one exists; otherwise a component of an FDA-approved drug; otherwise a substance on FDA’s list established by regulation. The ingredient must also come from a registered establishment with a valid certificate of analysis. | The bulk substance must be on FDA’s 503B bulks list, or the drug must be on FDA’s drug shortage list. The substance also needs a registered manufacturer and a certificate of analysis, and must meet a USP or NF monograph if one exists. |
| Copies of approved drugs | The statute bars compounding essentially copies of a commercially available drug “regularly or in inordinate amounts.” A change made for an identified patient that the prescriber determines produces a significant difference for that patient means the drug is not treated as essentially a copy. | Not being essentially a copy of an approved drug is a condition of the exemption. |
| FDA registration and oversight | Not registered with FDA as an outsourcing facility. State boards of pharmacy have primary oversight. | Registers with FDA each year (registration window: October 1 to December 31). FDA inspects on a risk-based schedule. |
| Reporting to FDA | The outsourcing-facility reporting duties do not apply. State board rules may impose their own. | Reports adverse events to FDA and submits product reports at initial registration and then each June and December. |
| Label | No 503B-style statutory label list applies. State board labeling rules apply, and other FD&C Act provisions still apply. | Must say “This is a compounded drug,” plus the facility name, address and phone number, lot or batch number, dosage form and strength, quantity, dates compounded and of expiration, storage and handling instructions, a list of ingredients, and “Not for resale.” FDA may specify a comparable alternative to the compounded-drug statement. |
| Shipping across state lines | The statute limits distribution outside the State to 5% of prescription orders unless the State has signed a memorandum of understanding with FDA. FDA’s state information page covers the standard MOU and where it stands; check it before relying on the 5% figure. | Not part of 503B. |
| FDA approval | Neither is FDA-approved. FDA says compounded drugs are not FDA-approved and that it does not verify their safety, effectiveness or quality before they are marketed. | |
Sources: 21 U.S.C. 353a, 21 U.S.C. 353b, FDA Compounding and the FDA: Questions and Answers, and FDA’s chart of FD&C Act provisions that apply to compounding. A general summary, not legal advice.
How to check who made it
- A pharmacy (503A). Look the pharmacy up in your state board of pharmacy’s license database. FDA’s BeSafeRx page links every state’s database and advises against using a pharmacy that is not listed. FDA: locate a state-licensed online pharmacy
- An outsourcing facility (503B). Check FDA’s list of registered outsourcing facilities, which FDA updates weekly. A facility that does not re-register in the October 1 to December 31 window is removed on January 1. The list does not show state board actions. FDA: registered outsourcing facilities
Related
- Questions to ask before buying a compounded medication (printable checklist for patients)
- Peptide compounding status tracker (where BPC-157 and five other peptides stand)
- Peptide Compounding Law for Pharmacists: 503A and the HHS Policy