FDA logs 990 adverse event reports for compounded semaglutide

As of May 31, 2026, the FDA has received 990 reports of adverse events associated with compounded semaglutide and more than 730 associated with compounded tirzepatide, according to the agency's page on unapproved GLP-1 drugs used for weight loss ^[1]. The FDA said the true totals are likely higher, because federal law does not require state-licensed pharmacies that are not outsourcing facilities to submit adverse event reports ^[1].

Semaglutide is the active ingredient in the approved drugs Ozempic, Wegovy and Rybelsus; tirzepatide is the active ingredient in Mounjaro and Zepbound. Compounded versions are mixed by pharmacies rather than the drugmakers, and they are not FDA approved, meaning the agency does not review them for safety, effectiveness or quality before they are marketed ^[1]. The FDA said many of the adverse events reported for compounded products appear to be consistent with those seen with the approved versions ^[1]. The agency also said it is not always possible to determine whether an adverse event resulted directly from the drug or whether other factors contributed ^[1].

Dosing errors and higher-than-label doses

The FDA said it has received multiple reports of adverse events, some requiring hospitalization, that may be related to dosing errors with compounded injectable semaglutide ^[1]. Those errors came from patients measuring and injecting the wrong dose and, in some cases, from health care professionals miscalculating doses ^[1].

The agency also received adverse event reports that may be tied to patients being prescribed compounded semaglutide or tirzepatide at doses beyond what the FDA-approved label calls for. That could mean more product in a single dose, doses taken more often, or a faster increase in dose than the approved schedule ^[1]. Reported symptoms included nausea, vomiting, diarrhea, abdominal pain and constipation, and the agency said some of these events were serious and some patients sought medical attention ^[1].

Quality, storage and fake labels

The FDA said some semaglutide sold by compounders may use salt forms, including semaglutide sodium and semaglutide acetate. Those are different active ingredients from the ones in the approved drugs, and the agency said it does not have information on whether they share the same chemical and drug properties and is not aware of any lawful basis for their use in compounding ^[1].

The agency also said it has received complaints that compounded GLP-1 drugs arrived warm or with inadequate ice packs, which can affect drug quality, and it recommends that multi-dose vials of sterile drugs be used within 28 days of first use because of contamination risk ^[1].

The FDA said it is aware of fraudulent compounded semaglutide and tirzepatide carrying false label information, including labels naming pharmacies that do not exist or naming a licensed pharmacy that, based on the agency's information, did not make the product ^[1]. One adverse event report described redness, swelling, pain, and a red lump at the injection site after use of a product labeled as compounded tirzepatide from a pharmacy that did not actually compound it ^[1].

The agency separately said retatrutide and cagrilintide cannot be used in compounding under federal law and have not been found safe and effective for any condition ^[1].

Why it matters for patients

The counts reflect reports submitted to the FDA, not confirmed causes, and the agency's own caveat means the number of problems linked to compounded GLP-1 drugs is probably larger than 990 and 730. Patients weighing compounded products against approved ones are comparing a reviewed supply against one the FDA says it does not review for safety, effectiveness or quality before marketing ^[1].

The FDA's stated position is that compounded drugs should only be used in patients whose medical needs cannot be met by an FDA-approved drug ^[1]. Its detailed concerns center on things a patient cannot easily check: whether the vial contains the same molecule as the approved product or a salt form, whether the concentration matches the label, and whether the drug stayed cold in transit ^[1].

Dosing is the most concrete risk described. Compounded injectable semaglutide often requires patients to measure their own dose from a vial rather than use a prefilled pen, and the FDA tied hospitalization-level reports to measuring errors by patients and calculation errors by clinicians ^[1].

Some practical questions are not answered in the FDA's accounting. The agency did not break down how many of the 990 or 730 reports were serious, how many involved hospitalization, which products or pharmacies were involved, or how the reports were verified. Those details have not been disclosed ^[1].