Clarifying Compounded GLP-1s: What the FDA Has Said

The most important thing to understand about compounded GLP-1s is what 'compounded' means — and what it doesn't.

What is drug compounding?

Compounding is when a pharmacy prepares a medication — often in a different form, strength, or dosage — to meet a specific patient's need. It is a legal, long-standing part of pharmacy practice. What it is not is a parallel manufacturing route: a compounder may not, regularly or in large amounts, produce something that is essentially a copy of an approved commercial drug.

What has the FDA said about compounded GLP-1s?

Two things, and the second one changed the market. First: compounded semaglutide and tirzepatide are not FDA-approved, are not interchangeable with the branded drugs, and may differ in purity and potency.

Second, and more consequential: the shortages that justified large-scale compounding are over. The FDA issued declaratory orders resolving the tirzepatide shortage in December 2024 and the semaglutide shortage in February 2025, then set deadlines through spring 2025 for compounders to stop. In April 2026 it proposed removing all three molecules — semaglutide, tirzepatide, and liraglutide — from the 503B bulk drug substances list.

Is compounded semaglutide still legal?

In a narrow sense, yes; in the sense most people mean, no. A 503A pharmacy can still compound a patient-specific preparation against a valid prescription where the prescriber documents a clinically significant difference from the approved product for that individual. What ended is the routine model: a standard formulation shipped to a broad population as a cheaper substitute for the branded drug.

One common workaround deserves a flag. Adding another ingredient — vitamin B12 is the usual example — does not automatically make a formulation something other than essentially a copy, and it is not evidence-backed as a way to improve GLP-1 results.

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

The two pathways are governed by different rules, and the distinction decides what is permitted now.

• 503A is a traditional compounding pharmacy. It prepares a medication for an individual patient against a specific prescription. It may not compound, regularly or in large amounts, something that is essentially a copy of an approved drug unless the prescriber documents a clinically significant difference for that patient.
• 503B is an outsourcing facility. It compounds in batches, without patient-specific prescriptions, and it works from bulk drug substances. That is only permitted when the bulk substance appears on FDA's 503B Bulks List, or when the drug is on FDA's shortage list at the time it is compounded, distributed, and dispensed.

Semaglutide and tirzepatide are currently on neither. They came off the shortage list in 2025, and in April 2026 the FDA proposed excluding them from the 503B Bulks List altogether. As the agency put it, when FDA-approved drugs are available, outsourcing facilities cannot lawfully compound from bulk drug substances absent a clear clinical need.

Why does FDA approval status matter to patients?

• You may be getting a product that hasn't gone through FDA approval for that exact form.
• Dosing and purity can vary between compounding sources.
• It's not the same product as the branded drug, even if the molecule name is the same.

What should you ask a provider about compounded GLP-1s?

Ask three things, directly. 'Is this the FDA-approved product or a compounded one?' 'If compounded, what clinically significant difference has the prescriber documented for me specifically?' And 'Can you show me the pharmacy, its licensure, and any third-party testing?' A reputable service answers all three plainly. Vagueness on the second one is the signal that matters most, because that is the question the current rules turn on.