How do you read an FDA warning letter, section by section?

The example

We use FDA's Dec. 12, 2025 letter to Pinnacle Professional Research, doing business as Pinnacle Peptides (MARCS-CMS 719337), described in our archive story. The structure below is what that one letter does. Other letters use other headings, especially for inspection-based letters.

Header

The top lists how it was delivered (this one by email), the recipient and place, the FDA reference number, the issuing center (here the Center for Drug Evaluation and Research) and the letter date. The date on the letter and the date FDA posts it are different; in letters we tracked, posting came 7 to 11 days later.

Opening paragraph

The opening says what FDA looked at and when. In this letter FDA says it reviewed the company's website in November 2025 and identifies the products it says were offered, which it describes as unapproved new drugs. It is the allegation in summary form.

The violation sections

• Safety concerns: FDA explains why it regards the product class as risky.
• Intended use: FDA argues that, despite research-only labeling, website content describing therapeutic effects shows the products are intended as drugs.
• Product-specific evidence: examples from each product page, such as disease claims.
• New drug status: FDA's reasoning that the products lack approval and are therefore unapproved new drugs.

What FDA asks for

The letter asks the company to respond within fifteen working days with the steps it took, how it will prevent recurrence, supporting documents, or its reasoning if it disagrees. It states that failure to correct may lead to regulatory or legal action, naming seizure and injunction.

The closing caveat

The letter says the violations it cites may not be all of them. It is FDA's stated position, not a court finding; see our pages on what a warning letter does and does not mean.