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FDA warning letters to peptide sellers: the patterns behind them

The FDA publishes the warning letters it sends, and reading them is one of the most useful things a research store owner can do. The letters to online sellers follow recognizable patterns. This guide describes those patterns in general terms so you can check your own store against them. It is general information, not legal advice, and the letters themselves are the primary source.

Updated September 28, 2026

What a warning letter is

A warning letter is a formal notice that the agency believes a company is violating the law. It usually lists the specific pages, statements or products involved and asks for a written response within a set time, commonly 15 working days. Letters are posted publicly on the FDA's website, where anyone, including your processor and your buyers, can read them.

Patterns that recur in public letters

  • Product pages or social posts describing what a compound does in the human body.
  • Instructions for use by people, including amounts, schedules or ways to take a product.
  • A research use only disclaimer sitting next to marketing clearly aimed at consumers.
  • Testimonials, reviews or customer photos describing what happened to the customer.
  • Selling products the agency regards as unapproved new drugs, or ones that copy approved medicines.

The disclaimer alone does not protect a store. Letters routinely quote the rest of the page to show who the products were really marketed to.

Run this review on your own store

  1. Read every product page as if you were a regulator: would a stranger think this is sold for use by people?
  2. Search your site, your emails and your social accounts for any mention of the body, of use, or of outcomes.
  3. Remove customer reviews that describe using the product on themselves, even when a customer wrote them.
  4. Check that your research use only statement is visible on product pages, at checkout and on labels.
  5. Keep a record of what you changed and when.

The free wording checker catches most of the risky phrasing in seconds.

If you receive a letter

Contact a lawyer who works with FDA matters before you respond, and keep everything the letter mentions exactly as it is until they advise you. Do not ignore the deadline.

How Purity helps

Purity checks the wording of product pages, emails and texts against a rule set built for research stores, and blocks the worst phrases before they publish or send. It keeps a log of changes, so you can show what your store said and when. It does not replace legal advice.

Common questions

Where can I read FDA warning letters?
On the FDA's website, which has a searchable list of warning letters by company, subject and date.
Does a research use only label make a store safe?
No. Letters look at the whole store: the pages, the emails, the social posts and the reviews. The label has to match how the product is actually marketed.
Should I respond to a letter myself?
Talk to a lawyer who handles FDA matters first. The response and its timing matter.

Let the back office run itself

Book a short demo and see this working with your own products and payment methods, or create an account and start setting up.