The Food and Drug Administration (FDA or Agency) is announcing the availability of a draft guidance for industry entitled “Interim Policy on Compounding Using Bulk Drug Substances Under Section 503A of the Federal Food, Drug, and Cosmetic Act” (draft guidance or 2023 503A Interim Policy Draft Guidance) to describe FDA’s interim policy regarding the use of bulk drug substances by human drug compounders that are not registered with FDA as outsourcing facilities while FDA develops the list of bulk drug substances that can be used in compounding under the applicable section of the Federal Food, Drug, and Cosmetic Act (FD&C Act). This draft guidance, when finalized, will replace the guidance for industry entitled, “Interim Policy on Compounding Using Bulk Drug Substances Under Section 503A of the Federal Food, Drug, and Cosmetic Act” issued in January 2017 (2017 503A Interim Policy Guidance).