FDA peptide enforcement tracker

What the letters have in common

Every letter to an online seller notes the “research use only” or “not for human consumption” wording on the site, then concludes from the rest of the evidence (product descriptions, reconstitution supplies, dosing information, marketing) that the products were drugs intended for people. Labelling alone did not protect any of these sellers.

In 2026 FDA sent letters in batches: four on March 31, one on June 17 and five on August 24. Most named GLP-1 class peptides such as semaglutide, tirzepatide and retatrutide. The August batch also named tesamorelin, SS-31 (elamipretide) and PT-141 (bremelanotide).

The May 2026 letter to Harbin Jixianglong Biotech is different: it followed an on-site inspection of a peptide API plant and cites CGMP deviations. Buyers sourcing API should check FDA inspection records for their manufacturer, not only its own certificates.

Open vs closed

A warning letter stays open until FDA posts a close-out letter confirming the issues were fixed. A missing close-out does not mean the company is still violating the law; it means FDA has not published a resolution.

How this affects directory scores

A listed supplier with an open FDA warning letter is capped at 60 and its listing shows a notice linking to the letter. See how we score suppliers.

Scope and corrections

The tracker covers warning letters that name peptide products. It does not cover import alerts, untitled letters, court cases or compounding pharmacy actions. A warning letter sets out FDA's findings and is not a court ruling. To report a close-out or an error, use the contact form.

Source: FDA Warning Letters database. Summaries are paraphrased; read the full letter for details.