Compounding narrows, and the category learns what "available" really meant

The FDA has proposed that semaglutide, tirzepatide and liraglutide not be included on the 503B bulks list, the list of bulk drug substances that outsourcing facilities are permitted to compound from. In its evaluation of the nominations, the agency stated it did not identify a clinical need for outsourcing facilities to compound these three substances from bulk.

The 503B bulks list matters because, in most cases, an outsourcing facility cannot compound a drug from a bulk substance unless that substance appears on the list or the drug is on the FDA shortage list. With the shortages resolved and the substances proposed for exclusion, both of the routes that made large-scale compounding of these medicines lawful are closing.

The agency opened a public docket for comment, which closed on 29 June 2026.

On 27 February 2026, the Secretary of Health and Human Services announced that roughly 14 of the 19 peptides then sitting on the FDA Category 2 restricted compounding list would be moved back to Category 1. Category 2 substances carry significant safety risks identified by the agency and are effectively off limits for compounding; Category 1 substances may be compounded while under evaluation.

This runs in the opposite direction to the GLP-1 news above, which is exactly why the two belong in the same issue. A blanket sentence about "peptides being banned" or "peptides being legalised" was wrong before this announcement and is wrong after it. The status is per substance, and it moves.

The FDA resolved the tirzepatide and semaglutide shortages and set deadlines for 503A pharmacies to stop compounding them, which passed in 2025. The shortage listing had been the legal basis for most compounded supply of these medicines, so its removal is the single largest structural change this category has been through.

The FDA has received hundreds of adverse event reports associated with compounded semaglutide and compounded tirzepatide. A recurring theme in the reports is dosing error: people drawing an incorrect amount from multidose vials, in a presentation that differs from the prefilled pens the approved products use.

This is reported here as a documented pattern in the agency record. It is not a statement about any individual product, pharmacy, or person.

The FDA has continued to issue warning letters to companies selling peptide products, including letters published in September 2025 and January 2026. The letters generally concern marketing unapproved new drugs and misbranding, and several concern products sold under research framing while being marketed for human use.