What FDA warning letters to research peptide sellers have in common

FDA has published warning letters to online sellers whose products were labeled for research use only. The letters reviewed for this page share a clear pattern. FDA acknowledged the "research use only" and "not for human consumption" statements on the sellers' labeling, then said that evidence from the sellers' own websites showed the products were intended to be drugs for human use.

This page describes, at a general level, what two recent public warning letters say, both of which can be found on FDA's warning letters page, and what FDA says about warning letters in general. It does not name the companies or products involved. It is not a summary of every letter FDA has sent, and it does not predict how FDA would view any other business.

What a warning letter is

FDA's page on warning and close-out letters explains that the agency issues a warning letter when it believes there are significant violations of federal requirements. The letter identifies the concerns, which can include problematic product claims, and gives the recipient an opportunity to address them. FDA asks for a response within a set timeframe. A recipient who disagrees can explain why and send supporting information.

FDA posts warning letters publicly on its website. Its page notes that some letters are redacted or edited to remove confidential information.

FDA may later issue a close-out letter after evaluating a firm's corrective actions. The same page says a close-out letter will not be issued based on representations that some action will be or has been taken. The corrective actions must actually have been made and verified by FDA.

Pattern 1: the website was the evidence

Both letters describe a review of the seller's website. The main evidence FDA relied on was the sellers' own product-page text. FDA quoted copy that described how the products were said to act in the body or what conditions they were said to address, and one letter noted that similar claims appeared on several pages.

None of this copy is reproduced here. The point is where it lived: on ordinary product and website pages that the sellers controlled.

Pattern 2: research-use statements did not change the finding

Each letter acknowledged that the seller's labeling carried statements such as "research use only" and "not for human consumption." Each then said that, despite those statements, evidence obtained from the seller's website or labeling established that the products were intended to be drugs for human use.

This is the core of the pattern. The disclaimer was noted, and then weighed against everything else the seller said.

Pattern 3: intended use was the legal hinge

Both letters refer to FDA's regulation on intended use, 21 CFR 201.128, and to the definition of a drug in the Federal Food, Drug, and Cosmetic Act. That regulation says intended use is the objective intent of those responsible for a product's labeling, shown by things such as labeling claims, advertising and the circumstances of distribution. From that starting point, the letters set out FDA's position that the products were new drugs being marketed without an approved application.

Our explainer on intended use, and why a label is not enough covers the regulation in plain language.

Pattern 4: what else was sold mattered

One letter pointed to other items the seller offered alongside its products. FDA said the sale of those items showed how the seller intended the products to be used together. The lesson is that the catalog as a whole, not only each product page, can be read as evidence of intended use.

Pattern 5: a short deadline and an open-ended scope

Both letters ask for a written response within fifteen business days of receipt. The response is to describe the specific steps taken to correct the violations, the steps taken to prevent them from happening again, and copies of related documentation. Both letters say the violations listed are not an all-inclusive list, and both warn that failing to address the violations may result in regulatory or legal action without further notice.

The common thread

Read alongside FDA's intended use regulation, the letters show the agency judging what a product is for from the seller's own words and conduct, not from the disclaimer. FDA's guidance on research-use-only diagnostic products makes a similar point in its own context: it says merely placing an RUO label on a product does not exempt it from requirements, and that FDA may look at other evidence, including how the product is marketed. That guidance is written for diagnostic products, but its reasoning about labels and evidence is consistent with what these letters say.

For more on the label itself, see what research use only means.

Questions a research supply store can ask itself

The letters concern specific sellers and specific facts. Still, they suggest practical checks for any store that uses a research-use-only label:

• If the disclaimer were removed, what would the rest of each product page say the product is for?
• Does any page describe effects in people or animals, conditions or outcomes? If so, remove that copy. Our list of claims to remove can help.
• Do you sell anything alongside your products that only makes sense for use outside a laboratory? If so, stop selling it, rather than changing how it is described.
• Have you checked old blog posts, FAQs and archived pages? They are part of your website too. See auditing old blog posts.
• Are affiliates or other promoters saying things about your products that you would not say?
• Do you keep a dated record of what your pages said and when you changed them?

Fixing copy after a letter arrives is not the same as keeping it consistent beforehand. FDA's own page is clear that close-out letters follow verified corrections, not promises.

What this page is not

This is a general description of public documents. It does not say whether any product may be sold, and it does not predict whether FDA would act in any situation. If you have received a letter from FDA, or are unsure about your products, speak to a qualified lawyer about your business promptly.

Claddr's weekly monitoring checks product pages, policies and checkout copy against your compliance profile and points to the exact line that needs attention, with a suggested fix. You decide what to change. Read more about how Claddr works.