# The FDA 503B Bulks List and Its Role

Canonical source: https://retacompare.com/research/fda-503b-bulks-list-64

FDA · 2026-01-17


    The 503B bulks list governs bulk drug substances that outsourcing facilities may use to prepare compounded sterile preparations for office use. Like the 503A list, the 503B list is narrow. FDA policy documents through 2025 and 2026 have clarified that bulk substances used by 503B facilities must be obtained from FDA-registered manufacturers and must appear on the applicable list. Peptides like tirzepatide, semaglutide, and retatrutide are not on the 503B bulks list. This has been a principal basis for recent FDA enforcement actions against 503B facilities that produced compounded GLP-1 preparations post-shortage.


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