Category 2 (FDA bulk drug substances)
Category 2 is a label on an FDA list for ingredients that compounders might want to use but that the FDA thinks may carry significant safety risks. If an ingredient is in Category 2, the FDA says it could take action against a compounder who uses it. The list changes over time, so the FDA page is the place to check.
For experts
Under FDA's interim policies on bulk drug substances nominated for the 503A and 503B bulks lists, Category 2 covers substances nominated with sufficient supporting information but for which FDA has identified significant safety risks. FDA does not extend the Category 1 enforcement-discretion policy to them and would consider taking action against compounding with them under its general enforcement policies. FDA publishes the identified risks and states that it does not intend to place substances nominated on or after 7 January 2025 into these categories. The list is revised by FDA and should be read from the source.
Sources (3)
- 01Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (Category 2)U.S. Food and Drug Administration · 2026-04-22 · accessed 2026-09-29
- 02Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C ActU.S. Food and Drug Administration · 2026-05-14 · accessed 2026-09-29
- 03Bulk Drug Substances Used in Compounding Under Section 503B of the FD&C ActU.S. Food and Drug Administration · 2025-01-07 · accessed 2026-09-29