Understanding FDA Compound Categories
How FDA 503A categories work, who they affect, and why a headline about Category 2 is not the same as an updated federal list.
Under Section 503A of the Federal Food, Drug, and Cosmetic Act, the FDA sorts bulk drug substances used in compounding into three categories. The list matters if you are a patient with a prescription, a prescriber, or a pharmacy trying to stay inside the lines. It is not the same thing as "FDA approved for sale as a finished drug."
Who actually feels this day to day
If you are not filling a 503A prescription at a licensed pharmacy, you might never read these lists. If you are, the category decides whether a bulk ingredient can legally be on the bench. Telehealth and compounding news dump acronyms fast; the boring version is: category controls what pharmacies can put in a compounded product for a human patient under US rules we are summarizing here, not replacing.
Category 1: allowed for compounding (when other rules also fit)
Category 1 substances are the ones the FDA has reviewed for the compounding context and placed on the "yes" side for 503A, subject to all the usual pharmacy law, prescriptions, and state boards. Category 1 is not a stamp that says "safe for every use." It means the FDA reached a formal position about compounding with that bulk ingredient.
Category 2: not allowed for 503A compounding
Category 2 is the stop list for those bulk substances under 503A. In September 2023 the FDA moved 19 substances to Category 2, including names people argue about online: BPC-157, TB-500, CJC-1295, Ipamorelin, and others. Pharmacies that follow US rules should not be compounding them for patients while they sit in Category 2.
Category 3: still being sorted
Category 3 is the holding pen: nominated, not fully decided. That can feel fuzzy because it is fuzzy. Check the published lists rather than trusting a forum screenshot.
February 2026 announcement vs. written FDA lists
On February 27, 2026, HHS Secretary Robert F. Kennedy Jr. said publicly that about fourteen of the nineteen Category 2 substances would move back toward Category 1. As of April 2026, treat that as politics plus a signal, not as filed guidance in your pocket. Until FDA publishes an updated list you can cite, Category 2 entries still read the way they read the day before the press conference.
Where to read the ground truth
Lists move. Your pharmacist's counsel beats a blog. When you need the raw text, pull it from FDA's own compounding bulk drug substance pages and PDF notices, not from a repost with no link. We refresh this guide when the formal lists change.
Compounding eligibility is not the same as drug approval
A peptide can be a marketed, FDA-approved drug and still be a mess in compounded form if supply, enforcement, and state rules disagree. Something can sit in Category 1 and still be inappropriate for a given patient. The category answers one narrow gatekeeping question for 503A bulk substances. Your prescriber and pharmacist answer the rest.