Regulatory explainer
What actually happened to peptides in 2026
Three separate things happened in 2026, and none of them changed what a compounder may lawfully use. Substances left an FDA list because the parties who nominated them withdrew the nominations. An advisory committee consultation was announced and has not yet taken place. A rulemaking was proposed and has not been finalised. Only the third kind of event changes a list.
Why this page exists
Three separate regulatory events took place in 2026, and a great deal of the coverage has compressed them into a single story about substances becoming available. They are not one story. They are three different kinds of administrative act, taken by different parties, with different legal consequences, and two of the three change nothing at all about what a compounder may lawfully use.
This page states only what named FDA documents say, quotes them where the wording carries the meaning, and links each one so you can read it yourself. It is dated 28 August 2026 at the top and carries a review date for a reason: the underlying documents move, and two of them moved within the four months before that date.
What are the three things being run together?
Strip the coverage away and three distinct acts remain.
| The event | Who acts | What it changes about what may be compounded |
|---|---|---|
| A nomination is withdrawn | The party that nominated the substance, not FDA | Nothing is permitted. The substance stops being evaluated |
| An advisory committee is consulted | An FDA advisory committee, giving advice | Nothing directly. Advice is not binding, and it is not a rule |
| A rule is issued | FDA, through notice-and-comment rulemaking published in the Federal Register | This is the step, and the only step, that changes the list |
The confusion is understandable, because all three concern the same list and all three generate documents. But a substance leaving a list because its sponsor stopped pursuing it is close to the opposite of that substance being cleared, and a consultation that has been announced but has not happened is not a finding of any kind.
What does it mean when a substance is "removed from the list"?
FDA's page on bulk drug substances that may present significant safety risks carries a second table, under this heading:
Bulk drug substances nominated but withdrawn — This list of bulk drug substances previously in category 2 of the interim policies were withdrawn by the nominators.
Read the last four words. The nominators withdrew. FDA did not clear anything, evaluate anything, or permit anything. A withdrawn nomination means the substance is no longer being evaluated for inclusion on the 503A bulks list at all — which removes a route rather than opening one.
There is a second document that makes this close to permanent. FDA's page on 503A bulk drug substances records that the agency revised the interim policy, and states the effect directly:
This guidance document states the agency does not intend to place bulk drug substances nominated on or after January 7, 2025, into these categories.
So the on-ramp that a withdrawn substance would need in order to come back is itself closed to new nominations.
Has the advisory committee consultation actually happened?
No. FDA's 503A category list, updated 14 May 2026, records one substance where the whole sequence is visible in a single passage: the nominations for GHK-Cu were withdrawn by the nominators on 22 April 2026, and on 5 May 2026 one of those nominators clarified that it had intended to withdraw only the injectable route of administration. The same note then says what comes next:
FDA has announced it intends to consult the Pharmacy Compounding Advisory Committee (PCAC) before the end of February 2027 regarding the potential inclusion of GHK-Cu on the 503A bulks list.
Two details in that passage are easy to lose. The clarification restored the non-injectable route to the enforcement-discretion tier described below, while the injectable route's nomination stayed withdrawn — so the two routes sit in different places and must never be described together. And the consultation itself is a future intention, stated in the present, about a meeting that had not occurred as of this page's review date. An advisory committee gives advice; FDA is not bound to follow it; and following it would still require the rulemaking described in the next section.
We state no vote count on this page, for that consultation or any other. Counts have been circulating in this market. None has been matched to a primary FDA document we have read, and an unverifiable number is worse than no number.
What is the only step that actually changes the list?
Rulemaking. The 503A bulks list is not a webpage or an announcement — it is a regulation, codified at 21 CFR 216.23, and it reads in full:
(a) The following bulk drug substances can be used in compounding under section 503A(b)(1)(A)(i)(III) of the Federal Food, Drug, and Cosmetic Act. (1) Brilliant Blue G, also known as Coomassie Brilliant Blue G-250. (2) Cantharidin (for topical use only). (3) Diphenylcyclopropenone (for topical use only). (4) N-acetyl-D-glucosamine (for topical use only). (5) Squaric acid dibutyl ester (for topical use only). (6) Thymol iodide (for topical use only).
The regulation's source note is [84 FR 4710, Feb. 19, 2019] — a Federal Register citation, because that is how the list was made and how it would have to be changed. Six substances. None of them is a peptide. Nothing that happened in 2026 added an entry to that section, and no announcement, list update, category note or committee agenda can, because none of those things is a rule.
What does a live rulemaking look like right now?
There is a current example, and it is instructive precisely because it is moving in the restrictive direction. On 30 April 2026 FDA announced a proposal to exclude semaglutide, tirzepatide and liraglutide from the 503B bulks list, with comments due by 29 June 2026.
That is the full anatomy of the third kind of event: a published proposal, a defined comment window, and then a determination. As of this page's review date the comment window has closed and no final determination has been located. A proposal is not a rule, a closed comment period is not a decision, and the correct description of that file today is "pending." Anyone describing it as settled, in either direction, is ahead of the document.
What did not change in 2026?
The underlying legal tests, which is the part worth memorising because it survives every news cycle.
For a state-licensed 503A pharmacy, a bulk drug substance must clear one of three prongs: comply with an applicable USP or NF monograph where one exists; failing that, be a component of a drug approved by the Secretary; failing that, appear on the list issued through rulemaking — the six-substance section quoted above. For a facility registered with FDA as an outsourcing facility under section 503B, FDA states the position in two limbs: such a facility may not compound a drug product that includes a bulk drug substance unless that substance appears on the 503B bulks list, or the drug product compounded from it appears on FDA's drug shortage list at the time of compounding, distribution and dispensing.
Why does claiming FDA endorsement matter here?
Because one codified sentence disposes of the entire genre of headline this page exists to correct. 21 CFR 216.23(d):
Any person who represents that a compounded drug made with a bulk drug substance that appears on this list is FDA approved, or otherwise endorsed by FDA generally or for a particular indication, will cause the drug to be misbranded under section 502(a) and/or 502(bb) of the Federal Food, Drug, and Cosmetic Act.
That is in the Code of Federal Regulations, not in guidance. It says that claiming FDA endorsement for a compounded drug is itself a violation — even for the substances that are on the list.
Note too what FDA's interim policy is and is not. Where the agency says it does not intend to take action against a compounder using a nominated substance under stated conditions, that is a statement about enforcement intent. It is not a determination that the substance belongs on the list, and it is not approval. It can also be revised, which is exactly what happened in January 2025.
A court decision is a fourth thing again
On 27 August 2026 the Fifth Circuit affirmed the district court in litigation over one of the shortage-list determinations, in an unpublished per curiam opinion: "For the foregoing reasons, we AFFIRM the district court's judgment." The mandate was scheduled to issue on 19 October 2026, so the decision was not yet final on this page's review date, and the companion appeal argued in March 2026 had no decision.
A court reviewing whether an agency acted reasonably is doing something different again from the three events above. It does not add or remove anything from a list. It decides whether a decision the agency already made survives review — which is why an affirmance changes the litigation and not the regulation.
When does this page stop being true?
Sooner than you would like, and that is the honest answer rather than a disclaimer.
The review date at the top is the date a person last read the sources named at the foot of this page, not the date the file was edited. This page is re-verified on a thirty-day cycle against four documents specifically: FDA's 503A bulk drug substances page and the category list PDF it links, FDA's page on substances that may present significant safety risks and its withdrawn-nominations table, the 503B bulks list, and the docket behind the April 2026 proposal. Two of those moved in the four months before this review.
If you are reading this well after the date at the top, treat it as a map of how to check rather than as the current state, and open the sources. That is also the standard to hold any supplier to: the citation, the version date, and the document itself. For how the same discipline applies to the state rules governing office stock, see the state-by-state office-use guide.