FDA warning letters to research peptide sellers, 2024–2026
This page lists FDA warning letters sent to online sellers of "research use only" peptides, with a link to each letter on fda.gov. It is the record our supplier labels rely on: any supplier with a letter on file is labelled Avoid and never linked.
- A "research use only" label did not protect any of these sellers. FDA judged intended use from the whole website.
- Evidence FDA cited includes health or body-function claims, dosing guidance, bacteriostatic water sold as a reconstitution solution, "peptide calculators" alongside that water, and GLP-1 code names such as "GLP-3 Reta".
- GLP-1 compounds (semaglutide, tirzepatide, retatrutide) appear in most letters.
FDA warning letters to research-peptide sellers
| Date | Company | What FDA cited | Letter |
|---|---|---|---|
| 24 Aug 2026 | TXP Innovations LLC (Tex Peptides) | Unapproved GLP-1 and other peptide drugs | #735067 |
| 24 Aug 2026 | Peak Performance Peptides | Research-styled GLP-1 wording ("appetite regulation and satiety pathways") treated as a drug claim | #735127 |
| 24 Aug 2026 | NuScience Peptides LLC | Bacteriostatic water and a peptide calculator; first letter naming survodutide and mazdutide | #733652 |
| 24 Aug 2026 | Royal Peptides LLC | Bacteriostatic water marketed with a peptide guide and peptide calculator | #734884 |
| 24 Aug 2026 | Peptide Partners LLC | GLP-1 code names ("GLP-3 Reta"), SS-31, PT-141, and bacteriostatic water sold as a reconstitution solution | #735063 |
| 17 Jun 2026 | Wholesale Peptide | Research-benefit wording on product pages treated as evidence of human drug use | #729447 |
| 31 Mar 2026 | Lovega LLC (Pink Pony Peptides) | Unapproved peptide drugs sold online | #721088 |
| 31 Mar 2026 | PekCura Labs | Unapproved peptide drugs sold online | #721709 |
| 31 Mar 2026 | Mile High Compounds LLC | GLP-1 product names and bacteriostatic water cited as unapproved drugs | #721600 |
| 31 Mar 2026 | Prime Sciences | Website evidence overrode "laboratory research purposes only" labelling | #721805 |
| 31 Mar 2026 | Gram Peptides | "Research use only" products found intended for human use from website claims | #721806 |
| 10 Dec 2024 | Prime Vitality Inc. (Prime Peptides) | Unapproved GLP-1 research compounds | #695156 |
| 10 Dec 2024 | Summit Research Peptides | Unapproved GLP-1 research compounds | #695607 |
| 10 Dec 2024 | SwissChems | GLP-1 research compounds (semaglutide, retatrutide) marketed as unapproved drugs | #695663 |
Letter dates are the dates on the letters. FDA often posts letters one to two weeks later; the 24 August 2026 letters were posted on 1 September 2026. A warning letter is an FDA advisory notice, not a court finding. Companies may have responded or changed their websites since.
Other enforcement reported in 2026
- July 2026: Paradigm Peptides founder sentenced in federal court after earlier FDA letters and a guilty plea (reported).
- 12 August 2026: Eli Lilly filed civil lawsuits against several sellers of research retatrutide (reported).
- 18 September 2026: FDA warned Empower Pharmacy, a licensed 503A pharmacy, over compounded GLP-1 blends.
- September 2026: a federal jury convicted the owner of an online "research" peptide seller, treating the disclaimer as deception (reported).
These items come from public court and press reporting summarised by the sources below; check the primary record before relying on them.
How to use this list
Before ordering for a lab, search the supplier's legal name on the FDA warning letters database as well as this page, since sellers often trade under several names. Then run it through our vendor check. For the regulatory background, see the July 2026 FDA peptide vote explainer.
Frequently asked questions
Does a "research use only" label make peptide sales legal?
Not by itself. In every letter listed here FDA looked past the label and judged intended use from the seller's whole website, including claims, dosing content and the sale of bacteriostatic water.
Why does FDA mention bacteriostatic water?
Selling it as a reconstitution solution alongside injectable peptides was treated as providing the means to prepare an injectable drug for human use.
Is a warning letter a conviction?
No. It is an advisory notice that FDA believes the company is violating the law. It can lead to further action if not corrected.
How often is this page updated?
We review FDA postings regularly and add new peptide-seller letters when they are published.
Sources
- FDA warning letters database
- Arent Fox Schiff: Five peptide vendors learn that research use only is not a legal strategy (18 Sep 2026)
- RAPS: FDA warning letters target marketers of unapproved weight-loss drugs (7 Apr 2026)
- McDermott: Federal regulators and state boards crack down on RUO peptides
- VialAudit: FDA peptide enforcement 2024–2026