503A vs. 503B Pharmacy: What It Means for Your Compounded GLP-1 or Peptide

A 503A pharmacy is a state-licensed pharmacy that compounds a drug for one named patient's prescription. A 503B outsourcing facility registers with FDA, is inspected by FDA on a risk-based schedule, and must follow the same current good manufacturing practice (CGMP) rules as drug makers. Neither one makes an FDA-approved drug. And of the 202 telehealth sellers on our boards in October 2026, 147 do not say which kind of pharmacy fills their orders.

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

The numbers are sections of the federal Food, Drug, and Cosmetic Act.

Section 503A covers a licensed pharmacist in a state-licensed pharmacy, or a physician. The drug must be "compounded for an identified individual patient based on the receipt of a valid prescription order"¹. Its raw ingredients must meet a U.S. Pharmacopeia monograph, be a component of an FDA-approved drug, or appear on FDA's own list¹. State boards of pharmacy do most of the day-to-day oversight; FDA steps in with surveillance and for-cause inspections³.

Section 503B was created in 2013. An outsourcing facility "is not required to be a licensed pharmacy" and "may or may not obtain prescriptions for identified individual patients"². In exchange it registers with FDA, reports what it made every June and December, files adverse event reports, and gets inspected on a risk-based schedule². Its drugs are subject to CGMP requirements; a 503A pharmacy's are not³. FDA keeps a public list of registered facilities⁵.

Which one can make compounded semaglutide or tirzepatide now that the shortages are over?

FDA declared the tirzepatide shortage resolved on December 19, 2024, and the semaglutide shortage on February 21, 2025⁴. For 503B facilities, the end dates for copying the approved drugs were March 19, 2025 (tirzepatide) and May 22, 2025 (semaglutide)⁴. In an April 2026 update FDA said neither drug "currently appear[s] on the 503B bulks list or on FDA's drug shortage list"⁴ — the two routes a 503B facility needs to compound from bulk ingredient².

A 503A pharmacy has more room, but not unlimited room. FDA treats a compounded drug as "essentially a copy" if it matches an approved product's active ingredient, strength range and route, unless the prescriber documents a significant difference for that patient⁴. That is why many sellers now add an ingredient or change the dose form. Our legality explainers for tirzepatide and semaglutide cover the details.

For peptides such as BPC-157, the question is different: whether the substance may be compounded at all. See our page on FDA's 503A bulks list review.

Is a 503B pharmacy "safer"?

It is held to stricter manufacturing rules and inspected by FDA on a schedule, which is a real difference²³. It does not make the drug FDA-approved: compounded drugs from either category skip FDA's pre-market review for safety, effectiveness and quality³. A well-run 503A pharmacy can be better than a poorly run 503B facility. The category tells you which rules apply and who inspects. It does not tell you about one specific pharmacy's record.

How many telehealth sellers tell you which pharmacy they use?

Few. Of the 202 sellers on our boards, 147 do not state a verifiable 503A or 503B category for the pharmacy that fills their orders. 50 say 503A, 3 say 503B, and 2 describe a network that uses both. Some of the 147 do name a pharmacy but contradict themselves about its category, so read "no stated category" as exactly that, not as "names no pharmacy."

Every seller's status, with the page we read it from, is on our pharmacy transparency page. Each review also prints the pharmacy line, and our price transparency page does the same exercise for prices.

How do I check a pharmacy myself?

1. 1.Ask the seller for the pharmacy's name and state. A seller that will not tell you is telling you something.
2. 2.For a 503B claim, search FDA's list of registered outsourcing facilities⁵. If the facility is not there, it is not operating as a 503B.
3. 3.For a 503A claim, look the pharmacy up on your state board of pharmacy's license search, and on the board of the state it ships from.
4. 4.Read the vial label when it arrives. A 503B label must say "This is a compounded drug" and name the facility². A 503A label names the dispensing pharmacy and you.

What should I ask a provider before ordering?

• •Which pharmacy fills my prescription, and is it a 503A pharmacy or a 503B outsourcing facility?
• •Is the medication made for me under my prescription, or shipped from stock?
• •What is on the vial besides the active ingredient (for example B12, B6 or glycine), and why?
• •What beyond-use date will the vial carry, and how should I store it?
• •Will the pharmacy change depending on my state?

Then compare the answers with the tirzepatide sellers, the semaglutide sellers or the sermorelin sellers we track. Each row shows the pharmacy category the seller states, or "Not disclosed."