The 2026 peptide enforcement timeline

How this timeline works

This is a record of what US government bodies did about peptides in 2026, each entry dated and tied to a government document. It leaves out rumours, seller announcements and anything we could not trace to an agency. A warning letter is the FDA's formal notice that it considers a company to be breaking the law; it is not a court finding, and companies can respond. Each status below is as of the date given.

Late 2025: the lead-in

December 19, 2025. In a warning letter, the FDA stated that ibutamoren, sold as MK-677, is excluded from the definition of a dietary supplement and warned that it may increase the risk of congestive heart failure in some people ¹. Ibutamoren is not a peptide, but it is sold beside them, and the letter set out the agency's position before the year began.

April to June: the Category 2 reset and the GLP-1 proposal

April 15, 2026. The FDA updated its list of bulk drug substances nominated for compounding under section 503A, giving notice that 12 peptides would leave Category 2, the group it treats as raising significant safety concerns, after seven days, because their nominations had been withdrawn ^{2 3}. Among them were BPC-157 Low and TB-500 Low. Leaving Category 2 did not put them on the 503A bulks list or into Category 1, the group where the FDA uses enforcement discretion, so compounding them remained a regulatory risk ³.

April 16, 2026. A Federal Register notice announced that the Pharmacy Compounding Advisory Committee would consider seven peptides for the 503A bulks list ⁴.

May 1, 2026. The FDA proposed not to include semaglutide High, tirzepatide High and liraglutide on the 503B bulks list, the list outsourcing facilities can compound from, with a 60-day comment period (91 FR 23431) ⁵. It was a notice, not a rule, and none of the three had ever been on the list.

June 26, 2026. A two-page Federal Register notice extended the comment period by thirty days, to 11:59 p.m. Eastern on July 30, 2026 (91 FR 38719) ⁶.

June 29, 2026. The FDA released one briefing document per peptide ahead of the committee meeting. In each, agency staff proposed not adding the substance to the 503A list, citing inadequate chemical characterisation, missing information on immune reactions, insufficient evidence of effectiveness, and approved drugs already available for the nominated uses ⁷.

July: the committee votes

July 23 and 24, 2026. The Pharmacy Compounding Advisory Committee recommended six of the seven peptides for the 503A list, against its own staff's proposals: BPC-157, KPV and TB-500 each by 8 votes to 6 with one abstention, MOTS-c by 7 to 5 with two abstentions, semax by 8 to 5, and epitalon. It voted down emideltide, also called DSIP, by 6 to 7 ⁷. The committee advises; it does not decide.

July 30, 2026. The comment period on the 503B GLP-1 proposal closed ⁶.

August and September: the warning letters

August 24, 2026. The FDA's drug center sent warning letters to five online peptide sellers in North Carolina, Florida, Texas and Arizona, and posted them on September 1. Each letter calls the named products unapproved new drugs whose sale across state lines violates sections 301(d) and 505(a) of the Food, Drug, and Cosmetic Act. Each also rejects the same defence: labels reading "research use only" or "not for human consumption" did not outweigh what the sellers' websites showed. The products named across the letters include semaglutide, tirzepatide and retatrutide, often under grey-market nicknames, along with survodutide, mazdutide, SS-31, PT-141, tesamorelin and a tesamorelin-ipamorelin blend ⁸.

September 18, 2026. In a warning letter posted September 22, the FDA told Empower Pharmacy, a large Houston compounding pharmacy, that its tirzepatide with niacinamide and semaglutide with vitamin B12 appear to be essentially copies of FDA-approved GLP-1 drugs, and that the volumes it produced suggest the added ingredients are a pretext. FDA investigators had inspected the pharmacy from November 3 to 14, 2025 ⁹.

Where things stand

At our last check on September 25, 2026, none of the six peptides the committee recommended had been added to the 503A list or moved into Category 1, so the legal position for pharmacies was the one that applied before the vote, and the FDA had not published its final determination on the 503B GLP-1 proposal ^{7 5}. For what these rules mean for anyone buying peptides online, see our guide to what "research use only" means; for compounded GLP-1 users, our GLP-1 transition guide covers the options.

Frequently asked questions

Did the FDA legalise BPC-157 in 2026?

No. On April 15, 2026 the FDA gave notice that BPC-157 and 11 other peptides would leave Category 2, but that did not put them on the 503A bulks list or into Category 1. The compounding committee recommended BPC-157 in July; at our last check on September 25, the FDA had not acted on that vote.

What did the FDA warning letters to peptide sellers say?

Five letters dated August 24, 2026 said the products named were unapproved new drugs and that 'research use only' or 'not for human consumption' labels did not outweigh what the sellers' own websites showed.

Can compounding pharmacies still make semaglutide and tirzepatide?

The FDA proposed on May 1, 2026 not to put them on the 503B list, and its comment period closed July 30. In September it also warned a large pharmacy that adding a vitamin does not stop a compounded GLP-1 from being a copy. At our last check, the final 503B decision had not been published.

Is a warning letter a conviction?

No. A warning letter is the FDA's formal notice that it considers a company to be breaking the law. It is not a court ruling, and the company can respond.

Related on Grey Peptides

• The PCAC votes, July 2026
• Losing compounded GLP-1 access
• What 'research use only' means

Sources

1. US FDA. Warning letter dated December 19, 2025, on ibutamoren (MK-677) products, as read at fda.gov for our MK-677 entry; re-read October 2, 2026.
2. US FDA. Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the FD&C Act: categories update, April 15, 2026.
3. Orrick, Herrington & Sutcliffe. FDA Announces Removal of 12 Peptides from Category 2 and Schedules PCAC Meetings to Consider Adding Peptides to 503A Bulk Drug Substances List, April 16, 2026; read October 2, 2026.
4. National Law Review. Tiny Chains, Big Changes? What FDA's Latest Actions Mean for Peptide Compounding, April 2026 (on the April 16, 2026 Federal Register notice); read October 2, 2026.
5. US FDA. FDA proposes to exclude semaglutide, tirzepatide and liraglutide from the 503B bulks list, May 1, 2026 (91 FR 23431); read October 2, 2026. FDA
6. Federal Register. List of Bulk Drug Substances for Which There Is a Clinical Need Under Section 503B: extension of the comment period to July 30, 2026, June 26, 2026 (91 FR 38719); read October 2, 2026. Federal Register
7. US FDA. Pharmacy Compounding Advisory Committee, July 23-24, 2026 meeting: briefing documents (posted June 29, 2026) and votes; read October 2, 2026. FDA
8. US FDA. Warning letters dated August 24, 2026 to five online peptide sellers, posted September 1, 2026 (one of the five linked); read October 2, 2026. FDA
9. US FDA. Warning letter to Empower Clinic Services LLC dba Empower Pharmacy, September 18, 2026, posted September 22, 2026; read October 2, 2026. FDA

Educational information, not medical advice. Each dose in this guide names its source, an approved label or a published study. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose.