Can a 503B outsourcing facility compound a given peptide?
Short answer · as of 2026-10-05
Only through two routes. An outsourcing facility may compound from a bulk drug substance if it is on FDA's 503B bulks list, or if the finished drug is on FDA's drug shortage list when it is compounded, distributed and dispensed. The 503B list on FDA's page had five substances when we read it, and none was a peptide. FDA proposed on Apr. 30, 2026 not to include semaglutide, tirzepatide or liraglutide.
By Peptide Industry Gossip · Published · General explanation, not legal or medical advice. Disclaimer.
The two routes
- The 503B bulks list: substances for which FDA has found a clinical need for outsourcing facilities to compound.
- The shortage route: the finished drug is on FDA's drug shortage list at the time of compounding, distribution and dispensing.
- The statute also says bulk substances must come from registered establishments, meet applicable monographs and come with a valid certificate of analysis.
What is on the 503B list
FDA's 503B list page, current as of May 16, 2024, names five substances: diphenylcyclopropenone, glycolic acid, quinacrine hydrochloride, squaric acid dibutyl ester and trichloroacetic acid. It mentions no peptide, including BPC-157, semaglutide, tirzepatide and liraglutide. FDA says it found no clinical need for 21 other substances it considered. The page date is old, so check FDA for the current list.
The GLP-1 proposal
On Apr. 30, 2026, FDA proposed not to include semaglutide, tirzepatide and liraglutide on the 503B bulks list, saying it found insufficient evidence of clinical need. Comments were open through June 29, 2026. It is a proposal, and we did not find a final decision.
What this does not tell you
- It does not cover 503A pharmacies, which have different ingredient rules. See our comparison.
- It does not say whether any particular facility compounds a given peptide.
- FDA's interim categories apply to nominated substances and are separate from the 503B list itself.
Sources
- FDA, Bulk Drug Substances Used in Compounding Under Section 503B of the FD&C Act (updated Jan. 7, 2025)
- FDA, 503B Bulk Drug Substances List (content current as of May 16, 2024)
- FDA, FDA proposes to exclude semaglutide, tirzepatide and liraglutide from the 503B bulks list (Apr. 30, 2026)
- Legal Information Institute, 21 U.S.C. 353b (FD&C Act section 503B)