Read this first
This is plain-language harm-reduction information, not medical advice. Peptides discussed here are research compounds; most are not approved for human use. People will use them either way — we would rather they have the facts.
On 30 April 2026 the US Food and Drug Administration announced a proposal to exclude semaglutide, tirzepatide and liraglutide from its "503B bulks list". According to the FDA, it found no clinical need for outsourcing facilities to compound these drugs from bulk substances.
What the 503B list is
In the US, "outsourcing facilities" (the 503B category) can make larger batches of compounded drugs, but generally only from bulk ingredients that are on an FDA list, or that are in an FDA-declared shortage. The FDA says that because approved versions of these three drugs are available, compounding them from bulk substances is not necessary.
What the FDA said
FDA Commissioner Marty Makary was quoted as saying: "When FDA-approved drugs are available, outsourcing facilities cannot lawfully compound using bulk drug substances unless there is a clear clinical need." The FDA opened a public comment period through the Federal Register docket, closing on 29 June 2026, and said it would review comments before a final determination.
What it does and does not change
Medical News Today, reporting on 10 May 2026, noted that this is a proposal, and that 503A pharmacies (which prepare medicines for individual patients on a prescription) may still compound GLP-1s, though that route is, in the words of the clinicians quoted, much more restricted and not designed for widespread use. One physician cited by the outlet said most current compounded supply comes through 503B facilities, which would no longer be able to compound in bulk if the proposal is finalised. Doctors quoted also raised concerns about contamination, impurities and incorrect dosages in some compounded products.
We have not seen a final decision in the sources we checked, so treat the proposal as proposed rather than in force.
Why it matters if you use or are considering GLP-1s
- Compounded does not mean the same as approved. Compounded versions are not FDA-approved, and quality can vary by supplier.
- If the supply of compounded products tightens, expect more grey-market sellers filling the gap. These are the sellers most likely to supply mislabelled, contaminated or wrongly dosed products.
- Do not stop or switch a medicine on your own because of a headline. If you are on a compounded product, talk to your prescriber about your options.
This is a US regulatory step. It does not change the UK position, where tirzepatide and semaglutide are prescription-only medicines and the MHRA warns against buying from unofficial sources.
What is still unknown
The final decision, its timing, and how many patients rely on 503B-sourced products are not stated in the sources we read. How the FDA will treat 503A compounding in practice is also unclear from the announcement.
Background reading: semaglutide and tirzepatide.
Common questions
Is compounded semaglutide now illegal in the US?
Not according to the sources we checked. The FDA proposal concerns bulk compounding by 503B outsourcing facilities; individual-prescription 503A compounding was described as still possible but restricted.