503A Pharmacy vs 503B Outsourcing Facility

	503A pharmacy	503B outsourcing facility
FDA status	State boards of pharmacy have primary day-to-day oversight. FDA does surveillance and for-cause inspections ^[2].	Registers with FDA, must follow CGMP and is inspected by FDA on a risk-based schedule ^{[1, 3]}.
Studied for	Bulk substances with a USP or NF monograph, parts of FDA-approved drugs, or on FDA's 503A bulks list ^[6]. No regular copies of commercial drugs ^[4].	Sterile drugs ^[3]. Bulk substances only if on the 503B clinical need list or the drug is in shortage ^[7]. No copies of approved drugs ^[5].
Route	Based on a valid patient-specific prescription, plus limited amounts made ahead based on order history ^{[1, 4]}.	With or without a patient-specific prescription. Drugs made without one are labeled "Office Use Only" ^{[1, 5]}.
Key trials	FD&C Act section 503A (21 U.S.C. 353a), the 503A bulks list and its interim categories ^{[4, 6]}.	FD&C Act section 503B (21 U.S.C. 353b), the 503B bulks list and CGMP rules ^{[5, 7, 3]}.
Who compounds	A licensed pharmacist in a state-licensed pharmacy or federal facility, or a licensed physician ^[4].	A licensed pharmacist or someone under their direct supervision. The facility need not be a licensed pharmacy ^[5].
Reporting to FDA	Not required to report adverse events to FDA, which FDA says leads to underreporting ^[8].	Must report adverse events and list its compounded drugs in June and December ^{[3, 5]}.
Distribution limits	In states without an FDA agreement, out-of-state shipments are capped at 5% of prescription orders ^[4].	Its drugs may not be sold or transferred by anyone other than the facility ^[5].

A 503A pharmacy compounds drugs for named patients with prescriptions, and its state board of pharmacy is its main overseer ^{[1, 2]}. A 503B outsourcing facility registers with FDA, follows drug-manufacturing quality rules (CGMP), and may make drugs with or without prescriptions ^[1]. For the full background, see 503A vs 503B pharmacies ^[1].

Where the two categories came from

Congress passed the Drug Quality and Security Act after the 2012 fungal meningitis outbreak. It was enacted on November 27, 2013, and created outsourcing facilities as a new, voluntary category ^[1]. Neither path produces an FDA-approved drug. FDA says compounded drugs are not FDA approved ^[2].

The biggest differences

Oversight is the first. State boards lead day-to-day oversight of 503A pharmacies, and FDA steps in for surveillance and specific problems ^[2]. Outsourcing facilities must meet CGMP and face FDA inspections on a risk-based schedule ^{[1, 3]}.

Prescriptions are the second. A 503A pharmacy compounds based on a valid prescription for an identified patient. It may make limited amounts ahead of time based on its order history ^[4]. An outsourcing facility may distribute with or without a patient-specific prescription. Drugs made without one must say "Office Use Only" on the label ^{[1, 5]}.

Ingredients are the third. A 503A pharmacy may use a bulk substance only if it meets a USP or NF monograph, is part of an approved drug, or is on FDA's 503A bulks list ^[6]. An outsourcing facility may use a bulk substance only if it is on the 503B clinical need list or the drug is on FDA's shortage list ^[7]. Both face limits on making copies of approved or commercial drugs ^{[4, 5]}.

Labels are the fourth. A drug from an outsourcing facility must carry the words "This is a compounded drug" and "Not for resale" ^[5]. Outsourcing facilities also register with FDA each year, between October 1 and December 31, and report the drugs they made twice a year ^[5].

Why it matters for peptides

A peptide that has no monograph and is not part of an approved drug can only be used by a 503A pharmacy if it is on the 503A bulks list ^[6]. For an outsourcing facility, it must be on the 503B list or the drug must be in shortage ^[7]. FDA places some substances in category 2 when it finds significant safety risks ^[7]. Check any peptide's status on the FDA Peptide Status Tracker ^[6].

Reporting also differs. Outsourcing facilities must report adverse events to FDA ^[1]. FDA says adverse events from compounded GLP-1 drugs are underreported because state-licensed pharmacies that are not outsourcing facilities do not have to report to FDA ^[8]. See compounded vs FDA-approved semaglutide for one example ^[8].

Frequently asked questions

What is the difference between a 503A and a 503B pharmacy?

A 503A pharmacy compounds based on patient-specific prescriptions under state board oversight. A 503B outsourcing facility registers with FDA, follows CGMP and may distribute with or without prescriptions ^{[1, 2]}.

Are 503B outsourcing facilities FDA approved?

They register with FDA and are inspected, but their drugs are still not FDA approved ^{[1, 2]}.

Can a 503B facility make drugs for office use?

Yes. It may distribute without a patient-specific prescription, and those drugs must be labeled "Office Use Only" ^{[1, 5]}.

Who inspects 503A pharmacies?

State boards of pharmacy have primary day-to-day oversight. FDA does surveillance and for-cause inspections ^[2].

Does a 503B facility have to be a licensed pharmacy?

No. The law says an outsourcing facility is not required to be a licensed pharmacy, but compounding must be done by or under a licensed pharmacist ^[5].

When were 503B outsourcing facilities created?

The Drug Quality and Security Act, enacted on November 27, 2013, created them ^[1].