# FDA has been sending warning letters to research-peptide sellers, and it just moved past the GLP-1s

> Source: https://peptidewellnessusa.com/news/fda-warning-letters-research-peptide-sellers-2026/
> News · Regulatory · July 2026
> By PeptideWellness Editorial Team · Updated September 23, 2026 · 10 min read

Eleven sellers of "research use only" peptides have been cited since March. The run was a GLP-1 story until June, when one letter named Prostamax and gonadorelin. On 24 August the agency sent five more at once, and every one of them names PT-141 and tesamorelin alongside the GLP-1s. FDA reviewed all five websites in July — the month its own advisers voted to recommend six peptides for legal compounding.

On June 17, 2026, the FDA sent a warning letter to a Florida company called Wholesale Peptide. The letter names two products: Prostamax and gonadorelin. Neither is a GLP-1.

That detail is the reason this page exists. For the last year and a half the agency's enforcement against websites selling peptides "for research use only" has been, in practice, enforcement against grey-market semaglutide, tirzepatide and retatrutide. The June letter is the first in the run to name the other kind of peptide — the bioregulator-and-hormone-analog end of the catalogue that the wellness market actually runs on. Five weeks later, FDA's own advisory committee voted to recommend six peptides for the legal compounding list.

Two months later the agency sent five more letters on a single day, and that detail stopped being an exception. Eleven sellers have now been cited since March. No established trade or general-interest outlet appears to have covered the March batch — searching the companies by name turns up FDA's own pages, a law-firm client alert, a safe-medicines advocacy roundup, a local television segment and a scattering of SEO and vendor-adjacent blogs, but nothing from the outlets that covered the parallel GLP-1 story. This page is our attempt to put it on the record properly. For the parallel enforcement track against telehealth companies marketing compounded GLP-1s, see our [June coverage](https://peptidewellnessusa.com/news/fda-warning-letters-compounded-glp-1-june-2026/); for the advisory vote, see [the committee's decision](https://peptidewellnessusa.com/news/pcac-peptide-vote-results-july-2026/). Letters to compounding pharmacies are a different charge reached a different way, and they have [their own register](https://peptidewellnessusa.com/learn/fda-warning-letters-compounding-pharmacies/).

## Who was cited

All eleven letters came from the same office — CDER's Office of Unapproved Drugs and Labeling Compliance — and all eleven carry the same signature, Captain Tina Smith, its director. The first six, through June:

| Seller | Location | Issued | Substances FDA named |
| --- | --- | --- | --- |
| Lovega LLC dba Pink Pony Peptides | Wellington, FL | Mar 31, 2026 | "GLP-2 TZ," "GLP-3 RT," bacteriostatic water |
| Gram Peptides | Rancho Santa Fe, CA | Mar 31, 2026 | Retatrutide, tirzepatide, "Bacteriostatic Water for Injection" |
| Prime Sciences | Scottsdale, AZ | Mar 31, 2026 | Cagrilintide, mazdutide, "GLP1-R," "GLP1-S," "GLP1-T," BAC water |
| Mile High Compounds LLC | Clifton, CO | Mar 31, 2026 | "GLP-1 SM," "GLP-2 TRZ," "GLP-3 RT," BAC water |
| PekCura Labs | Pensacola, FL | Mar 31, 2026 | "GLP-1-S," "GLP-2-T," "GLP-3-R," a "Cag (1mg) Tirz (10mg) Blend," bacteriostatic water |
| Wholesale Peptide | Brooksville, FL | Jun 17, 2026 | Prostamax, gonadorelin |

The code names are the sellers' own. FDA quotes them back and, in most of the letters, supplies the translation: Prime Sciences' "GLP1-R" is retatrutide, "GLP1-S" is semaglutide, "GLP1-T" is tirzepatide. Gram Peptides sold retatrutide under the name "GLP-1-R peptide" and tirzepatide as "GLP-2 peptide" — numbering that does not correspond to anything pharmacological.

Then, on August 24, five more at once:

| Seller | Location | Issued | Substances FDA named |
| --- | --- | --- | --- |
| Royal Peptides LLC | Boynton Beach, FL | Aug 24, 2026 | Tirzepatide, semaglutide, retatrutide, SS-31, PT-141, tesamorelin, "BIMORELIN" |
| Peptide Partners LLC | Sarasota, FL | Aug 24, 2026 | "GLP-1 S," "GLP-2 T," "GLP-3 Reta," SS-31, "Tesa Peptide," PT-141, "Reconstitution Solution (BAC)" |
| NuScience Peptides LLC | Cornelius, NC | Aug 24, 2026 | "GLP-2 Tirz," "GLP-1 Sema," "GLP-3 RT," survodutide, mazdutide, PT-141, tesamorelin, a tesamorelin-ipamorelin blend, BAC water |
| TXP Innovations LLC dba Tex Peptides | Dallas, TX | Aug 24, 2026 | Semaglutide, tirzepatide, retatrutide, SS-31, tesamorelin, PT-141, "Bacteriostatic Water 0.9% Benzyl Alcohol (10 ml)" |
| Peak Performance Peptides | Phoenix, AZ | Aug 24, 2026 | "Bac water," "GLP-3R," semaglutide, SS-31, PT-141, tesamorelin |

Three things in that table are worth stopping on.

**PT-141 and tesamorelin appear in all five.** The June letter was the first in the run to name something other than a GLP-1; the August batch makes that the pattern rather than the exception. [SS-31](https://peptidewellnessusa.com/peptides/ss-31/) — elamipretide, approved in September 2025 for Barth syndrome and sold here as a research chemical — appears in four of the five. Tesamorelin and PT-141 both have approved versions on the US market, as Egrifta and Vyleesi, which is exactly why selling unapproved copies of them is a drug offence rather than a grey area.

**NuScience was selling survodutide and mazdutide.** Neither can be lawfully sold in the United States, for two different reasons. Survodutide is investigational everywhere — Boehringer Ingelheim's own June 2026 trial announcement states that it "has not been approved for use." Mazdutide is approved, but in China: the NMPA cleared it for chronic weight management in June 2025 and for type 2 diabetes that September. It has no US approval, and mazdutide had already appeared once in this run, in the March letter to Prime Sciences. A drug approved in one country is still an unapproved new drug when sold in another.

**And the water is now itemised as a drug, not argued into being one.** In the March letters FDA reasoned its way there — the water is sold alongside injectables, therefore it is a drug. In August it simply appears in the list of unapproved new drugs at the top of the letter, by the seller's own product name: "Bacteriostatic Water 0.9% Benzyl Alcohol (10 ml)" at Tex Peptides, "Reconstitution Solution (BAC)" at Peptide Partners, "Bac water" listed first of six at Peak Performance.

Royal Peptides got the furthest extension of that reasoning. Where Prime Sciences had been caught by a kit containing water and a syringe, Royal was caught by documentation: FDA writes that the firm markets bacteriostatic water "alongside a 'peptide guide' and 'peptide calcul[ator,]' resources that collectively provide the means to prepare an injectable drug for human administration." The syringe became the instructions. A store that teaches you how to dose the product has said what the product is for.

Every one of the eleven pleads a single count: unapproved new drug, under sections 505(a) and 301(d) of the Food, Drug and Cosmetic Act, reached through the drug definition in 201(g)(1) and the new-drug definition in 201(p). No misbranding charge appears in any of the eleven letter bodies. That is worth stating precisely, because FDA's own portal labels the Wholesale Peptide letter "Unapproved New Drugs/Misbranded" while the letter itself contains no misbranding allegation at all — no 502, no reference to adequate directions for use. The word appears only in the index.

## The month FDA was reading these websites

Every one of the five August letters states when the agency reviewed the site. All five say July 2026.

FDA's Pharmacy Compounding Advisory Committee met on July 23 and 24 and voted to recommend six peptides for the legal compounding list. So the same month its advisers were arguing for a lawful channel, the agency was building five cases against the unlawful one. The letters went out a month later.

That timing is the clearest available answer to a question a lot of people asked after the vote, which was whether the July recommendation signalled a softer FDA. It did not, and the procedure explains why it could not. An advisory committee does not put anything on the 503A list. FDA's own description of the process is that it addresses nominated substances "on a rolling basis through notice-and-comment rulemaking" — a proposed regulation, a public comment period, then a final regulation. The committee is consulted along the way; it does not decide. FDA has published no timetable for responding to the July recommendations, and until a final regulation issues, the agency's position on these substances is the one in the letters.

One more letter went out the same day, to BioDrive, Inc., and it is worth separating from the five. That one is not a research-peptide case: it concerns a dietary supplement, "Evolv GLP-1 Biomimetic," and the count is an adulterated supplement containing a new dietary ingredient without adequate safety evidence. No research-use disclaimer, no bacteriostatic water, a different section of the Act. Two enforcement theories, one day.

## What FDA actually says about "research use only"

This is the part worth reading if you buy peptides online, because the agency has now said the same thing eleven times since March, which makes it a position rather than an opinion.

FDA does not argue with the disclaimer. It does not claim the label is fraudulent or that the seller is lying about their intentions. It makes a narrower and more durable move: the disclaimer loses to the rest of the website. The construction is identical from letter to letter, with only the quoted disclaimer changing. To Pink Pony Peptides: "Despite statements on your product labeling marketing your products for 'laboratory research purposes only' and '[n]ot for human consumption,' evidence obtained from your website establishes that your products are intended to be drugs for human use."

To Gram Peptides, the same sentence with "Research Use Only" and "not intended for human consumption, medical use, or veterinary use" swapped in. To Mile High Compounds, with "in vitro research and educational purposes only." To PekCura Labs, whose disclaimer FDA quotes with four of its own "[sic]" markers, preserving the seller's capitalisation errors in the record.

In the Wholesale Peptide letter the same holding survives but has been demoted to a footnote below the signature block, and slightly rephrased — evidence obtained "from your product labeling, including your website." Same doctrine, less prominence.

The legal machinery underneath is 21 CFR 201.128, the intended-use regulation. Intended use is established by the objective evidence of what a seller means the product for, not by what the label disclaims. A disclaimer is one piece of evidence. Marketing copy, dosing information and the way products are sold together are others, and they can outweigh it.

## The bacteriostatic water holding

The most concrete thing in these letters, and the one least likely to be understood by buyers, concerns the water.

Peptides sold as lyophilised powder have to be reconstituted before injection. Sellers routinely offer bacteriostatic water alongside them. FDA's position is that this pairing makes the water itself a drug. From the Mile High Compounds letter: "Your firm offers 'BAC Water' for sale alongside peptide products, which are drugs intended for injection and require reconstitution, including the above-mentioned products. The sale of these products together demonstrates that you intend for your 'BAC Water' to be used in combination for injection. Therefore, your 'BAC Water' is a drug."

The same paragraph, with the product name changed, appears verbatim in the Pink Pony, Gram and PekCura letters. Five of the six carry some version of the holding. It is absent only from the Wholesale Peptide letter, which names no water and no injection equipment.

Prime Sciences got the sharpest version, and it is the fifth. That firm sold a "Reconstitution Kit" containing BAC water and a syringe, and FDA treated the syringe as the tell: "The sale of a kit containing the 'BAC water' and a means of injection (a syringe) with these peptide drugs demonstrates that you intend for the 'BAC water' to be used in combination for injection."

The practical reading for a buyer: the store's own product bundling is evidence about what the store intends. A research reagent does not ship with a means of injecting it into a person.

## Where FDA looked for evidence

Two of the letters show the agency reaching past the storefront.

Mile High Compounds linked from its site to a community forum hosted on Skool. FDA reviewed both, from January to March 2026, and drew evidence not only from the shop pages but from documents circulating in the forum — a file called "The Ultimate Mile High Compounds Peptide Cheat Sheet" and a set of per-compound sheets. What those documents contained was dosing guidance written for people. FDA quotes it directly: for "GLP-3 RT (Retatrutide)," uses listed as weight loss and addiction recovery, dosing "Start: 1mg - 2mg weekly. Titrate up to: 12mg weekly." Parallel entries for tirzepatide and semaglutide. None of that is research-reagent documentation, and none of it was on the part of the site a casual visitor would see first.

PekCura Labs went the other way and it also failed. That seller wrote in careful clinical prose and cited the literature — Lincoff 2023, Marso 2016 and others — while almost never naming the molecules, using code names and doses instead. FDA treated the scientific framing itself as evidence of intended use. Writing like a pharmaceutical company about a product you say is not a pharmaceutical is not a defence.

## What has happened since

Less than you might expect.

As of FDA's own portal, current to September 22, 2026, **no response letter and no closeout letter has been posted for any of the eleven**. That is worth stating carefully: FDA posts responses selectively, and its standard notice warns that matters described in a warning letter may have been the subject of later interaction that changed the regulatory status. Absence of a posted closeout is not proof that nobody replied. What it does mean is that FDA has not publicly recorded any of these eleven as resolved.

None of the eleven has been the subject of a publicly announced seizure or injunction, which is the escalation the letters themselves threaten.

What has changed since this page first ran is the rate. Through June the run read as occasional: five letters on one day in March, one in June. The five posted on September 1 nearly doubled it in a single issue date, and they went out five weeks after the advisory vote that was widely reported as a loosening.

We attempted to check what each seller's website looks like today and could not complete it — several are now behind login gates or automated bot verification. We are not going to characterise what has changed on pages we could not properly read. What we can say is that none of the six appears to have exited.

## How this squares with the July vote

Two FDA tracks pointed in opposite directions this summer, and it is worth being precise about why that is not actually a contradiction.

On June 17 the agency told a seller that offering Prostamax and gonadorelin to the public was distribution of unapproved new drugs. On July 23 and 24 its Pharmacy Compounding Advisory Committee voted to recommend BPC-157, KPV, TB-500, MOTS-c, epitalon and semax for the 503A bulks list, rejecting only emideltide. Through that same July the agency was reading five more seller websites, and on August 24 it wrote to all five.

These are different questions. The advisory vote is about whether a licensed pharmacy may compound a substance from bulk against a prescription for a specific patient. The warning letters are about websites selling vials to anyone with a card, under a label that says the contents are not for human use. Nothing the committee recommended would make the second thing legal. If anything the two moves fit together: the argument several committee members made for a legal compounding channel was precisely that it would draw demand away from the grey market the letters are aimed at.

What has not changed is the bottom line for a buyer. None of these substances is an approved drug. None is on the 503A positive list today. FDA has issued no final determination. For what the compounding pathways actually are, see our [compounded versus branded explainer](https://peptidewellnessusa.com/learn/compounded-vs-branded/); and the seller-side signal that matters most is the one FDA acted on in every letter above: a vendor that labels product "research use only" while marketing it for human use is not operating inside any compounding pathway at all.

## References

1. [FDA — Warning Letter, Wholesale Peptide, MARCS-CMS 729447, June 17, 2026.](https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/wholesale-peptide-729447-06172026)
2. [FDA — Warning Letter, Lovega LLC dba Pink Pony Peptides, MARCS-CMS 721088, March 31, 2026.](https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/lovega-llc-dba-pink-pony-peptides-721088-03312026)
3. [FDA — Warning Letter, Gram Peptides, MARCS-CMS 721806, March 31, 2026.](https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/gram-peptides-721806-03312026)
4. [FDA — Warning Letter, Prime Sciences, MARCS-CMS 721805, March 31, 2026.](https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/prime-sciences-721805-03312026)
5. [FDA — Warning Letter, Mile High Compounds LLC, MARCS-CMS 721600, March 31, 2026.](https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/mile-high-compounds-llc-721600-03312026)
6. [FDA — Warning Letter, PekCura Labs, MARCS-CMS 721709, March 31, 2026.](https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/pekcura-labs-721709-03312026)
7. [FDA — Warning Letter, Royal Peptides LLC, MARCS-CMS 734884, August 24, 2026.](https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/royal-peptides-llc-734884-08242026)
8. [FDA — Warning Letter, Peptide Partners LLC, MARCS-CMS 735063, August 24, 2026.](https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/peptide-partners-llc-735063-08242026)
9. [FDA — Warning Letter, NuScience Peptides LLC, MARCS-CMS 733652, August 24, 2026.](https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/nuscience-peptides-llc-733652-08242026)
10. [FDA — Warning Letter, TXP Innovations LLC dba Tex Peptides, MARCS-CMS 735067, August 24, 2026.](https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/txp-innovations-llc-dba-tex-peptides-735067-08242026)
11. [FDA — Warning Letter, Peak Performance Peptides, MARCS-CMS 735127, August 24, 2026.](https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/peak-performance-peptides-735127-08242026)
12. [FDA — Warning Letter, BioDrive, Inc., MARCS-CMS 731846, August 24, 2026.](https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/biodrive-inc-731846-08242026)
13. [FDA — Warning Letters portal (subject lines, response and closeout columns, posting dates; content current as of September 22, 2026).](https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/compliance-actions-and-activities/warning-letters)
14. [Boehringer Ingelheim — Positive data from two Phase III SYNCHRONIZE obesity trials, June 7, 2026 ("Survodutide is an investigational agent and has not been approved for use").](https://www.boehringer-ingelheim.com/us/human-health/metabolic-diseases/positive-data-two-phase-iii-synchronize-obesity-trials)
15. [Shirley M. Mazdutide: First Approval. *Drugs*, 2025 — first approval granted in China, June 2025, for long-term weight management.](https://pubmed.ncbi.nlm.nih.gov/40679770/)
16. [FDA — Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act.](https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-act)
17. [FDA — Drugs@FDA: EGRIFTA (tesamorelin acetate), NDA 022505, approved November 10, 2010.](https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=022505)
18. [FDA — Drugs@FDA: VYLEESI (bremelanotide acetate), NDA 210557, approved June 21, 2019.](https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=210557)
19. [21 CFR 201.128 — Meaning of "intended uses."](https://www.ecfr.gov/current/title-21/chapter-I/subchapter-C/part-201/subpart-A/section-201.128)
20. PeptideWellness — [FDA's advisory panel overruled its own reviewers on six of seven peptides](https://peptidewellnessusa.com/news/pcac-peptide-vote-results-july-2026/), July 27, 2026.

> Editorial note: Informational only — not medical advice. A warning letter states FDA's allegations; it is not a finding of liability by a court, and recipients have an opportunity to respond. FDA's own notice cautions that matters described in a warning letter may have been the subject of subsequent interaction that changed the regulatory status of the issues discussed. None of the substances named on this page is an FDA-approved drug. Decisions about peptide therapy should be made with a licensed healthcare provider familiar with your medical history. Last reviewed September 2026.