FDA updates its unapproved GLP-1 guidance with compounded tirzepatide adverse event counts

The FDA has updated its standing safety page on unapproved GLP-1 drugs used for weight loss, adding new adverse event tallies for compounded versions of the two most-used molecules. As of May 31, 2026, the agency said it had received 990 reports of adverse events associated with compounded semaglutide and more than 730 associated with compounded tirzepatide ^[1]. Combined, that is more than 1,700 reports ^[2].

The agency attached an important caveat to both numbers. Federal law does not require state-licensed pharmacies that are not outsourcing facilities to submit adverse event reports to the FDA, so the agency said it is likely that adverse events from compounded versions of these drugs are underreported ^[1]. The FDA also noted it is not always possible to tell whether a reported problem was caused by the drug itself or by other factors, and that many of the reported events appear consistent with side effects seen with the FDA-approved versions ^[1].

What the FDA flagged

Beyond the counts, the page details several specific quality and safety problems the agency has seen.

Fraudulent products are one. The FDA said it is aware of fraudulent compounded semaglutide and tirzepatide sold in the U.S. with false label information. In some cases, the compounding pharmacy named on the label does not exist. In others, the label carries the name of a real licensed pharmacy that, based on information the FDA gathered, did not compound the product ^[1]. The agency said it knows of one reported adverse event tied to a product labeled as compounded tirzepatide from a pharmacy that did not actually make it; the report described redness, injection site swelling, pain and a red lump at the injection site ^[1].

Dosing is another. The FDA said it received multiple reports of adverse events, some requiring hospitalization, that may be related to dosing errors with compounded injectable semaglutide — errors that came from patients measuring and self-administering incorrect doses, and in some cases from health care professionals miscalculating doses ^[1]. The agency has also received reports possibly linked to compounded semaglutide or tirzepatide prescribed above what appears in the approved labeling, including larger single doses, more frequent dosing, or faster titration. Some of those events were serious, with patients reporting nausea, vomiting, diarrhea, abdominal pain and constipation ^[1].

The page also covers shipping and storage. Injectable GLP-1 drugs require refrigeration, and the FDA said it has received complaints that some compounded GLP-1 drugs arrived warm or with inadequate ice packs ^[1]. For multidose vials, the agency generally recommends discarding sterile vials 28 days after first use because of contamination risk, even if the compounder's instructions say otherwise, and using a new sterile needle and syringe each time ^[1].

On ingredients, the FDA said retatrutide and cagrilintide cannot be used in compounding under federal law and have not been found safe and effective for any condition ^[1]. It said semaglutide salt forms — semaglutide sodium and semaglutide acetate — are different active ingredients from the one in approved drugs, and the agency is not aware of any lawful basis for their use in compounding ^[1]. It has also warned companies selling unapproved products containing semaglutide, tirzepatide, retatrutide, survodutide or mazdutide labeled "for research purposes" or "not for human consumption" but sold to consumers with dosing instructions ^[1].

Why it matters for patients

The headline numbers are reports, not confirmed cases of harm. A report in FDA's system means someone flagged a problem, not that the drug caused it ^[1]. At the same time, the agency's own statement that the totals are undercounts means the true number of problems is unknown ^[1][2].

The practical takeaway is about where a product comes from and what is on the label. If a pharmacy name on a package cannot be verified, or the address or spelling looks wrong, the FDA lists those as telehealth red flags, along with deep discounts, no screening by a licensed prescriber, and medicine that looks different from what a local pharmacy dispensed ^[1]. The agency's general position is that compounded drugs should only be used when an FDA-approved drug cannot meet a patient's medical need, and that prescriptions should be filled at a state-licensed pharmacy ^[1].

The context has shifted. Becker's reported that the FDA has outlined restrictions barring pharmacies from compounding GLP-1s once branded versions leave the shortage list, and that in April the agency proposed excluding semaglutide, tirzepatide and liraglutide from the 503B bulks list while citing a facility for sterility failures ^[2]. Eli Lilly tightened rules for telehealth partners in 2025, requiring platforms including Ro and LifeMD to stop selling compounded tirzepatide and semaglutide ^[2].

What happens next

The FDA page is a standing document it updates periodically, so the next tally will cover a later cutoff than May 31, 2026 ^[1]. A specific date for that update is not stated in the sources. The agency continues to encourage patients, clinicians and compounders to report problems through MedWatch ^[1].