FDA Proposes Excluding Tirzepatide and Semaglutide From the 503B Compounding Bulks List

What Did the FDA Propose on 30 April 2026?

On 30 April 2026, the FDA announced it is proposing not to add semaglutide, tirzepatide or liraglutide to the 503B Bulks List — the list of bulk drug substances that FDA-registered outsourcing facilities may use to compound medicines at scale.[1] The agency's stated conclusion, after reviewing the nominations it received for all three substances, was that it "did not identify sufficient clinical need for outsourcing facilities to compound these drugs from bulk drug substances."[1]

The proposal was formally published in the Federal Register on 1 May 2026, opening a 60-day public comment window that was originally set to close in late June.[2] On 26 June 2026, the FDA published a further notice extending that window by 30 days, moving the deadline to 30 July 2026 — a delay the agency said "appropriately balanced allowing adequate time for interested persons to submit comments with avoiding significant delay of Agency action."[3] As of this article's publication, the docket remains open and the FDA has not issued a final determination.

What Is the 503B Bulks List, and Why Does It Matter?

Section 503B of the Federal Food, Drug and Cosmetic Act lets FDA-registered outsourcing facilities compound drugs in bulk, ahead of any individual prescription, and ship them to hospitals and clinics. Because these facilities are not held to the same standards as conventional drug manufacturers, the statute restricts what they can compound: a bulk drug substance generally has to appear on the 503B Bulks List, or the finished drug has to be listed on FDA's drug shortage database at the time of compounding, distribution and dispensing.[1]

Semaglutide, tirzepatide and liraglutide are the active ingredients in already-FDA-approved branded products — Ozempic and Wegovy, Mounjaro and Zepbound, and Saxenda and Victoza respectively. Outsourcing facilities compounded large volumes of these three ingredients during the 2022–2024 supply shortages of the branded injectors, which was lawful under the shortage exception. Once FDA removed semaglutide and tirzepatide from the drug shortage list, outsourcing facilities lost that legal basis and nominated all three substances for permanent addition to the 503B Bulks List instead — the determination the FDA proposed to reject on 30 April.[1]

What Does "Clinical Need" Mean in This Determination?

Under Section 503B, FDA can only add a bulk drug substance to the compounding list if it determines there is a "clinical need" for outsourcing facilities to compound it — broadly, that a compounded version serves a legitimate medical purpose an approved, commercially available product cannot meet. With semaglutide, tirzepatide and liraglutide now widely available as approved branded and (per the FDA's own April announcement) increasingly generic products, the agency's proposed reading is that the original clinical need — a drug shortage — has passed, and no independent need remains to justify permanent bulk compounding.[1]

Compounding-pharmacy trade groups and telehealth prescribers who built recurring revenue around lower-cost compounded GLP-1 injections have pushed back during the comment period, arguing patient cost and access still justify a compounded alternative. The FDA's proposal, if finalised as written, would not affect compounding under the drug-shortage exception should a future shortage recur — it would only close the permanent bulks-list route being sought here.

How Does This Differ From the Separate 503A Review of BPC-157 and TB-500?

It is worth being precise about which FDA proceeding is which, because both are moving through the docket system in July 2026 and cover overlapping territory — peptide-class drugs and compounding law — without overlapping substantively.

Our Sandoz generic-tirzepatide ANDA guide covers a third, again distinct, tirzepatide-related filing: the standard Hatch-Waxman generic-drug pathway, which has no bearing on either compounding docket. For the day-by-day 503A agenda, see our PCAC hearing schedule guide.

What Should UK Researchers Take From This?

The 503B Bulks List, the outsourcing-facility framework, and the "clinical need" standard applied here are all specific to the US prescription-drug supply chain. None of it changes the regulatory status of tirzepatide as a research reagent under UK law, and none of it has bearing on the Human Medicines Regulations 2012 or MHRA guidance that governs research-reagent supply in Great Britain and Northern Ireland.

It is also a useful contrast with retatrutide, a compound this determination does not touch at all: retatrutide has no FDA-approved branded product, so it is not eligible for either the 503A or 503B compounding pathways discussed above — it remains available in the US only through Eli Lilly's own clinical-trial programme, as covered in our retatrutide approval timeline guide.

Velox Peptides does not stock semaglutide, tirzepatide or liraglutide; our metabolic-research range is built around retatrutide, supplied strictly as an HPLC-verified in vitro research reagent with a batch-specific certificate of analysis in our public CoA library — entirely separate from any branded product, US compounding-pharmacy pathway, or the docket described in this article.

Compounds referenced here are discussed for regulatory-news context only and are not all stocked by Velox Peptides. Where supplied, compounds are research reagents only, not medicines, and have not been evaluated by the MHRA or FDA in our products. Not for human or veterinary use. See our Research Use Policy and MHRA Statement.

Frequently Asked Questions