FDA warning letters to peptide companies - the living tracker

The tracker: every letter, one line each

Here is the full list, with the specific thing on the site that did the damage. Names below are companies named in public FDA correspondence - this is the public record, not commentary on anyone's character.

We keep one-page teardowns of the load-bearing letters: Summit Research (Dec 2024), Pinnacle Peptides (2025), Gram Peptides (2026), Prime Sciences (2026), and PekCura (2026).

The through-line: totality, not the label

If you read all nine letters back to back, one phrase keeps recurring in different clothes: the FDA determines intended use from the totality of the circumstances. Not from your disclaimer. Not from the "research use only" badge in your header. From everything on the site, read together, the way a customer reads it.

That means an RUO banner on every page buys you nothing if page three of your blog explains reconstitution ratios and page five hosts a review that says "took two weeks to feel it." The banner says research; the totality says human use; the totality wins. Every letter in the tracker is a variation on that single move. We break the legal doctrine down properly in the intended-use doctrine guide - it is the one piece of law every peptide operator should actually read.

The disclaimer is a sentence. The site is the argument. The FDA grades the argument.

The March 2026 batch - seven letters, one doctrine

March 31, 2026 was the day the pattern stopped being deniable. Seven letters went out at once, all to research-peptide vendors, all citing unapproved new drugs and misbranding under the FD&C Act, and all built on the same evidentiary skeleton: screenshots of the vendor's own site.

What the batch established, in practical terms:

• Volume. One letter in 2024 could be an outlier. Seven in a day is a program. The agency has a template, a target list, and a repeatable process - which means the marginal cost of letter number eight is near zero.
• Screenshots are the evidence. The letters quote product pages, blog posts, and review widgets verbatim, with capture dates. Whatever your site said on the day they crawled it is what you answer for. "We took that down" is a mitigation, not a defense.
• Cross-sells count. Bacteriostatic water, syringes, and alcohol wipes sold alongside vials were cited as evidence of intended human use. The accessory aisle told the story the disclaimer tried to deny.
• GLP-1-adjacent compounds drew the most fire, consistent with the agency's broader compounding enforcement - but the citations were about presentation, not just compound choice.

The coded-name pattern: Prime Sciences and PekCura

Two of the March letters deserve their own section because they killed a strategy half the industry was quietly relying on: renaming.

The theory went like this - if a compound is radioactive, list it under an internal code name or an abbreviation, keep the real name off the page, and the crawlers and regulators will miss it. Prime Sciences and PekCura both ran versions of this play. The FDA's letters named the coded products and identified the underlying compounds anyway, in writing, in a public document. The agency pierced the code names without apparent effort - because a code name only works on people who do not know the market, and the FDA's reviewers demonstrably do.

The operational lesson is blunt: a name never changes a compound's regulatory status. If a compound is a problem under its real name, it is the same problem under a clever one - now with an added misbranding angle and a paper trail showing you knew enough to hide it. Full teardown in the Prime Sciences letter breakdown.

The origin letter: Summit Research, December 2024

Before the batch, there was one. The December 2024 letter to Summit Research Peptides was the first modern warning letter aimed squarely at a research-peptide storefront, and it set the template everything since has followed: the FDA quoted the site's own product descriptions - dosing suggestions, expected effects, stacking guidance - and held them up next to the RUO disclaimer to show the contradiction.

At the time, plenty of operators read it as a one-off. Fifteen months and eight more letters later, it reads as the opening move. If you sell peptides online and have never read a warning letter end to end, start with this one - it is short, specific, and every sentence maps to something you can check on your own site tonight.

Beyond GLP-1s: the Pinnacle letter

The 2025 letter to Pinnacle Peptides matters because it broke the comfortable theory that enforcement was really about semaglutide and tirzepatide knockoffs. Pinnacle's citations covered SARMs and research chemicals presented with fitness and physique framing. Different compound class, identical doctrine: the site's presentation implied human use, so the products were unapproved new drugs regardless of the research label.

If your catalog contains zero GLP-1s and you have been treating that as your compliance strategy, this is the letter that says it is not one.

The triggers, ranked

Collapse all nine letters and the same site elements keep appearing. Ranked roughly by how often they show up in the citations:

1. Dosing and administration content - protocols, reconstitution guides, dosing calculators. Cited in effectively every letter. This is the single fastest way to convert an RUO store into an unapproved drug seller in the agency's eyes.
2. Benefit and disease claims - "supports recovery," "studied for healing," condition names anywhere in copy. Even hedged, even in a blog post from 2023 you forgot about.
3. Human-use cross-sells - bacteriostatic water, syringes, injection kits. The Gram Peptides letter made this explicit; the accessory aisle is read as evidence of what the vials are for.
4. Customer reviews describing personal use - user-generated content is still your content. PekCura's letter cited reviews the company merely hosted.
5. Coded or renamed compounds - see Prime Sciences and PekCura above. Worse than useless: it adds intent.
6. Imagery implying use - injection photos, before/after body shots, clinical-treatment scenes. A vial photo is fine; a person mid-injection is a citation.

Notice what is not on the list: selling peptides. Every company in this tracker could have carried a defensible catalog with a defensible presentation. The letters punish the presentation.

What to do before your store reads like these

The uncomfortable part of maintaining this tracker is how ordinary the cited sites were. These were not scam operations - they were normal peptide stores with normal copy that nobody had read the way a regulator reads. Here is the checklist we would run today, in order:

• Read your site as a totality, once, honestly. Every page, every blog post, every review, every alt text. If a stranger would conclude your products are for people, so will the FDA. Our full peptide website compliance checklist walks the whole surface item by item.
• Kill the accessory aisle. No bac water, no syringes, no kits. The margin on those SKUs is not worth being paragraph three of your own warning letter.
• Purge dosing language everywhere - product pages, FAQs, old blog posts, email templates. The letters quote archived content; deleting it today still beats leaving it up.
• Turn reviews off or moderate them hard. Hosted use-descriptions were citable in 2026. They will be citable tomorrow.
• Check your catalog against the compound-level reality, under real names - and if anything on it only survives under a code name, it does not survive.
• Then keep watching. Enforcement doctrine moved three times in eighteen months. A site that passed in 2024 fails in 2026 without changing a word, because the bar moved. The rules keep moving; a human has to keep up.

If you want the fast version of step one, our free 60-second audit scans your storefront against the trigger list from these exact letters - grade on screen, report in your inbox, no signup. It is the same first pass we run on every site we take on.

This enforcement wave is also half the answer to a bigger question operators keep asking - why are peptide companies shutting down - because the letters and the payment-processor purges feed each other: a public warning letter is exactly what a processor's risk desk searches for before terminating an account.

Questions, answered straight

This page is general information for store operators, compiled from public FDA correspondence. It is not legal advice, and Stonegate Systems is not a law firm.