FDA has removed certain bulk drug substances that were placed on the category two list and has announced it will consult the Pharmacy Compounding Advisory Committee (PCAC) for potential future inclusion of Sources: U.S. Food and Drug Administration (FDA) Compounding and the FDA (503A & 503B guidance) FDA warning letters on unapproved peptide products National Institutes of Health (NIH) PubMed The FDA just put peptides like BPC 157, TB 500, and KPV on the clock. , As a compounding pharmacist, this is literally my world and most people dont understand the regulatory nuance behind what FDA Sends Warning Letters to More Than 50 GLP 1 Compounders and Manufacturers Wilson Sonsini