# The Legal Basis for Compounded Drugs in the US

Canonical source: https://retacompare.com/research/legal-basis-compounded-drugs-5

Compounded Peptides · 2026-01-09


    United States compounding pharmacy law is governed principally by Sections 503A and 503B of the Federal Food, Drug, and Cosmetic Act. Section 503A covers traditional compounding for identified individual patients pursuant to a valid prescription. Section 503B, added by the Drug Quality and Security Act of 2013, created a category of 'outsourcing facilities' that can produce compounded drugs in bulk for clinician office use. Both provisions require the compounded preparation to be based on an FDA-approved reference drug or a substance on the appropriate bulks list, and both prohibit essentially copying a commercially available product. These statutory boundaries form the legal foundation for virtually every FDA enforcement action related to compounded tirzepatide or semaglutide.


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