Anyone following peptide news over the past year has likely seen references to the FDA "removing" a peptide from one list or "advancing" it toward another, often in the same news cycle, which can make the actual regulatory status of a given peptide genuinely confusing. The confusion is understandable: the FDA's bulk drug substance evaluation system for compounding pharmacies involves two separate lists with very different meanings, and moving off one does not automatically mean moving onto the other.
The Legal Backdrop
Under Section 503A of the Federal Food, Drug, and Cosmetic Act, state-licensed compounding pharmacies can only use bulk drug substances that meet specific criteria, including appearing on an FDA-recognized list, unless the substance is the active ingredient in an FDA-approved drug. Because many popular research-chemical peptides, like BPC-157 and TB-500, are not FDA-approved drugs on their own, whether they can legally be compounded at all depends heavily on where they sit in this evaluation system.
Category 1: The "May Compound" List
Category 1 substances are those the FDA has evaluated and decided not to raise safety concerns significant enough to prevent compounding while a more permanent rulemaking process continues. In practice, the FDA has extended enforcement discretion to substances on this list, meaning it generally will not take action against pharmacies compounding them, even though formal rulemaking may still be pending. This is the list a substance generally needs to reach before compounding it is broadly considered legally supportable.
Category 2: The "Do Not Compound" List
Category 2 is essentially the opposite: substances the FDA has evaluated and found to raise significant safety concerns, based on the available data at the time of review. Substances placed here are generally considered ineligible for compounding, and pharmacies compounding them risk FDA enforcement action. A number of popular research-chemical peptides, including BPC-157 and TB-500, were placed in Category 2 in past FDA reviews.
Why Removal From Category 2 Doesn't Mean Automatic Approval
This is the step that trips up a lot of coverage of FDA peptide news. On April 15, 2026, the FDA published notice of its intent to remove twelve peptide substances, including BPC-157, TB-500, GHK-Cu (injectable forms), KPV, MOTS-c, Epitalon, Semax, Melanotan II, PEG-MGF, DSIP, Dihexa acetate, and Cathelicidin LL-37, from Category 2. That removal means the FDA no longer considers the safety concerns that originally justified blocking these substances to be current or sufficient on their own, which is a meaningful step. But removing a substance from the "do not compound" list does not automatically place it on the "may compound" list; those are two separate FDA determinations. A substance can, at least temporarily, sit in a kind of regulatory middle ground, no longer formally blocked but not yet formally cleared either, until the FDA takes the additional, distinct step of adding it to Category 1.
The Next Step: The Pharmacy Compounding Advisory Committee
That additional step is exactly what the FDA's Pharmacy Compounding Advisory Committee (PCAC) meeting on July 23-24, 2026 addressed, when the committee voted on whether to recommend adding several of these same peptides to Category 1. This site's coverage of that advisory panel vote and of specific peptides like KPV and MOTS-c covers what an advisory committee recommendation does and does not guarantee, since the FDA is not obligated to follow every advisory committee recommendation, and a final rule can still take additional time to formalize.
The Bottom Line
None of this changes whether these compounds are FDA-approved drugs, which they are not. It changes only whether a licensed compounding pharmacy can legally prepare them under Section 503A. Tracking a peptide's actual legal status requires checking both lists, and the dates each determination was made, rather than treating a single headline about one list as the full picture.