Compounded semaglutide and tirzepatide draw an FDA warning over fake labels and dosing errors

The FDA is warning patients and prescribers that compounded semaglutide and tirzepatide are not the approved medicines they copy. Its list of concerns covers fake pharmacy labels, warm shipments, dosing errors and salt forms with no known lawful basis. The agency's report counts run to 31 May 2026 and its page carries a 1 October date, so this is a reminder of standing guidance rather than a new ruling. For our board it is a safety and access story, not a stage move: the approved peptides stay approved, while two pipeline ingredients are named as off limits for compounding.

What the FDA page says and when

The statement sits among the agency's drug alerts under the title of its concerns with unapproved GLP-1 drugs used for weight loss. Its core point is legal and simple. A compounded drug is not FDA approved, so the agency does not check it for safety, effectiveness or quality before it reaches patients. The FDA says compounding can make sense when a patient's need cannot be met by an approved product, or when that product is not commercially available. It also tells patients to get a prescription from their doctor and fill it at a state-licensed pharmacy. The approved semaglutide brands Ozempic and Wegovy from Novo Nordisk, and the tirzepatide brands Mounjaro and Zepbound from Eli Lilly, are not the target of the warning.

The page states that its content is current as of 1 October 2026, and its adverse event counts stop at 31 May 2026. A local report by Atlanta News First on 6 November brought the guidance back into view, but nothing in either text points to a newer FDA update. The table below sets out the main items the agency lists, using its own figures where it gives one. Two caveats apply to every row. The FDA says it cannot always tell whether a reported problem came from the drug itself or from other factors. It also says many reports for compounded semaglutide and tirzepatide look like the known side effects of the approved versions.

FDA adverse event reports and dosing errors

The FDA adverse event reports are the hardest numbers on the page. By 31 May 2026, the FDA had logged 990 adverse event reports linked to compounded versions of semaglutide and more than 730 linked to compounded versions of tirzepatide. The agency adds that the true totals are probably higher. Federal law does not require state-licensed pharmacies that are not outsourcing facilities to send such reports to the FDA, so many problems may never reach its database. Some cases involving compounded semaglutide needed hospital care. The agency links part of the reports to dosing errors, where patients measured the wrong amount from a vial or a clinician made a calculation mistake, and part to prescriptions that went beyond what the approved labels allow.

By 31 May 2026, the FDA had logged 990 adverse event reports linked to compounded versions of semaglutide and more than 730 linked to compounded versions of tirzepatide.

Going beyond the label can mean a larger single amount, more frequent use or a faster climb than the approved schedule. Reported symptoms include nausea, vomiting, diarrhea, abdominal pain and constipation, the same stomach effects that are familiar from the approved drugs. The FDA asks prescribers to be vigilant when they set amounts and schedules for compounded tirzepatide and semaglutide, and asks patients to check with their prescriber or compounder how to measure what was intended. Fraud adds a second layer. The agency says some compounded products carry labels naming pharmacies that do not exist, or naming a real licensed pharmacy that did not make them. One report tied to such a falsely labelled tirzepatide product described redness, swelling, pain and a red lump on the skin.

Retatrutide and cagrilintide cannot be compounded

The FDA states that retatrutide and cagrilintide cannot be used in compounding under federal law. Neither is part of an approved drug, and the agency says neither has been found safe and effective for any condition. It has warned telehealth companies that marketed retatrutide, in some cases directly to consumers, ingredient distributors that sold retatrutide and other GLP-1 drugs to compounders, and outsourcing facilities that repackaged retatrutide. Both names matter to our board. Eli Lilly's retatrutide, a weekly triple agonist, is in Phase 3. Cagrilintide is the amylin analog that Novo Nordisk pairs with semaglutide in CagriSema, which sits at the filed stage. Neither molecule moves because of this warning, but both already draw enough illegal trade for the FDA to act.

The retatrutide compounding ban fits a wider pattern of demand running ahead of the evidence. Our earlier report on Malaysia, where officials seized unregistered retatrutide units, showed the same pull toward a molecule that has not finished its trials. The FDA also says it has warned firms that sold semaglutide, tirzepatide, retatrutide, survodutide or mazdutide labelled for research use or not for human consumption, while selling directly to consumers with instructions for use. Survodutide from Boehringer Ingelheim is in Phase 3, and mazdutide from Innovent is approved in China but not in the US. The practical point is plain. A research label on a vial does not make a product legal for people, and the agency calls these products of unknown quality.

What the warning changes for approved brands

Part of the warning is about the physical product. Injectable GLP-1 drugs need refrigeration, and the FDA has received complaints that some compounded shipments arrived warm or with too few ice packs. It tells patients not to use any injectable GLP-1 drug that arrives that way. For vials that hold several doses, it advises throwing the vial away 28 days after first use, even if medicine is left, and using a new sterile needle and syringe every time. The agency also flags semaglutide salt forms, such as semaglutide sodium and semaglutide acetate, sold by some compounders. These are different active ingredients from the one in the approved drugs, and the FDA says it knows of no lawful basis for using them.

On the pipeline board, approved semaglutide and tirzepatide stay where they are, so the signal is flat. The warning targets copies, not the brands, and it adds no new safety finding for the approved drugs. What it does is spell out the risks outside the approved supply chain. The FDA says it knows of counterfeit Ozempic in the US market and of illegal online sellers, and it uses an import alert to stop GLP-1 ingredients with possible quality problems at the border unless they come from makers that appear compliant. What remains unknown is how many reported harms were caused by compounded semaglutide itself, and how many fake products circulate. The agency's route to safe access is a prescription and a licensed pharmacy.

Conclusion

The FDA warning on compounded semaglutide and tirzepatide moves no molecule on our board, but it gathers the agency's main concerns about copies in one place: false labels, warm deliveries, salt forms, dosing mistakes and research labelled sales. Its counts are dated and likely too low. Watch for the next update of the FDA page and its report totals, further warning letters that name retatrutide or cagrilintide, and any change to the import alert. This story is research reporting, not medical advice.