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The FDA 503A bulks list, explained for peptide buyers

What section 503A allows a pharmacy to compound from, what the bulks list and its three interim categories are, what happened to peptides on September 29, 2023 and since, and what 'nominated but withdrawn' and a PCAC discussion actually mean for the product in front of you.

By FormBlends editorial teamUpdated September 4, 2026Educational, not medical advice

Most of the regulatory sentences on this site are variations on one theme: not on the list. This page explains what the list is, so those sentences carry their weight. Our compounding site has the longer version with the meeting-by-meeting history; this is the peptide buyer's edition.

Three doors

Section 503A of the Food, Drug, and Cosmetic Act lets a licensed pharmacy compound a drug for an individual patient from a bulk drug substance only if the substance passes through one of three doors:

  1. It has a monograph in the United States Pharmacopeia or National Formulary.
  2. It is a component of an FDA-approved drug.
  3. It appears on a list FDA develops by regulation: the 503A bulks list.

Tesamorelin and bremelanotide go through door 2, because Egrifta and Vyleesi exist. Sermorelin's position rests on door 2 and a discontinued product. No research peptide on this site has a monograph, and none is on the list. So their status is entirely a question of door 3 and the interim policy FDA uses while the list is built.

How the list is built, and how slowly

Anyone can nominate a substance. FDA reviews the nomination, takes it to the Pharmacy Compounding Advisory Committee (PCAC), a panel of twelve voting members, which votes on a recommendation. FDA then publishes a proposed rule, takes comments, and issues a final rule. The first final rule came in February 2019 and placed six substances on the list. The pace has not quickened since. A substance is on the list when a final rule says it is, and not one day before.

The three interim categories

Because rulemaking takes years and nominations came in by the hundred, FDA published an interim policy sorting nominated substances into categories:

  • Category 1. Nominated with enough information to evaluate, and may be eligible. FDA does not intend to take action against a 503A compounder using the substance while evaluation continues, provided the other 503A conditions are met. As of the category list updated May 14, 2026, NAD+ and non-injectable GHK-Cu are here.
  • Category 2. Nominated with enough information, but FDA has identified significant safety risks. FDA may take action. FDA publishes the safety concern for each substance on a dedicated page.
  • Category 3. Nominated without enough information to evaluate. Not covered by the interim policy.

On January 7, 2025 FDA revised the policy so that substances nominated on or after that date are not placed in any category at all.

September 29, 2023: the peptide day

On that date FDA placed a group of peptides in Category 2, citing in each case a risk of immunogenicity from aggregation or peptide-related impurities, difficulty characterising the active ingredient, and little or no human safety data. The group included BPC-157, TB-500, CJC-1295, ipamorelin, MOTS-c, injectable GHK-Cu, semax, selank, epitalon and AOD-9604: ten of the fourteen substances on this site.

Since then FDA's Category 2 page (content current as of April 22, 2026) has split them. Ipamorelin acetate remains listed in Category 2 under the 503B policy. The other nine appear in a second table headed "nominated but withdrawn," each still accompanied by FDA's safety concern. Withdrawal is procedural; the concern stands. That is why the X flag applies to all ten.

What PCAC did in 2024 and 2026

  • October 29, 2024: ipamorelin, ibutamoren, L-theanine and kisspeptin-10. FDA's briefing recommended against listing each.
  • December 2024: AOD-9604, CJC-1295 in several forms, thymosin alpha-1.
  • July 23, 2026: BPC-157, KPV, TB-500 and MOTS-c, with proposed uses of ulcerative colitis, wound healing and inflammatory conditions, wound healing, and obesity and osteoporosis respectively.
  • July 24, 2026: emideltide, semax and epitalon.

FDA's July meeting page (content current as of August 6, 2026) carried the agenda and briefing documents. It did not carry vote tallies when we checked. Trade press has reported outcomes; we do not repeat them as fact. FDA has separately said it intends to bring GHK-Cu to the committee before the end of February 2027.

What this means when you are holding a vial

Ask which door the substance came through. If the answer is a product name (Egrifta, Vyleesi), door 2, and the compounded version is still not that product. If the answer is "it's in Category 1," that is an enforcement posture during evaluation, not a finding of safety. If the answer is "it was withdrawn from Category 2" or "PCAC recommended it," the substance is outside 503A until a final rule says otherwise. If the answer is "it's sold for research," you are not holding a compounded drug at all; the salt forms and research-use-only page explains what you are holding.

The FormBlends report on the state of peptides and GLP-1 regulation in 2026 puts this alongside the GLP-1 shortage rules in one document.

Questions people ask

If a peptide was 'withdrawn from Category 2,' is it now allowed?

No. FDA's Category 2 page lists withdrawn substances in a separate table and keeps its safety concerns beside them. Withdrawal means the nomination was withdrawn or the substance moved into the advisory committee process. It does not place the substance in Category 1 or on the 503A bulks list, and it does not satisfy any of the three 503A routes.

What did the July 2026 advisory committee meeting change?

As of FDA's page dated August 6, 2026, nothing in law. The committee discussed BPC-157, KPV, TB-500 and MOTS-c on July 23 and emideltide, semax and epitalon on July 24. FDA's page carried the agenda and briefing materials, not vote tallies. Even a favourable vote leads only to a proposed rule, a comment period and a final rule, and only the final rule adds a substance to the list.

Where does 'research use only' fit in?

Nowhere in 503A. A product sold as research-use-only is not a compounded drug, is not made by a pharmacy under a prescription, and makes no claim to identity, sterility or potency for human use. The compounding site's page on salt forms and research-use-only labelling explains what that label does and does not promise.

Sources

  1. FDA: Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act (content current as of May 14, 2026) Accessed September 4, 2026.
  2. FDA: Bulk Drug Substances Nominated for Use in Compounding Under Section 503A, category lists (updated May 14, 2026) Accessed September 4, 2026.
  3. FDA: Certain Bulk Drug Substances for Use in Compounding That May Present Significant Safety Risks (content current as of April 22, 2026) Accessed September 4, 2026.
  4. FDA: July 23-24, 2026 Meeting of the Pharmacy Compounding Advisory Committee (content current as of August 6, 2026) Accessed September 4, 2026.
  5. Federal Register, February 19, 2019: List of Bulk Drug Substances That Can Be Used To Compound Drug Products in Accordance With Section 503A (final rule) Accessed September 4, 2026.
  6. Federal Register, January 7, 2025: Interim Policy on Compounding Using Bulk Drug Substances Under Section 503A; Guidance; Availability Accessed September 4, 2026.

Canonical URL: https://formblendspeptides.com/guides/fda-503a-bulks-list-explained. Written by the FormBlends editorial team. This page is educational and is not medical advice; see the medical disclaimer.