The US Food and Drug Administration has documented over 1,700 adverse-event reports related to illegal compounded versions of semaglutide and tirzepatide, amid rising regulatory scrutiny and ongoing market disputes in the lucrative obesity drug sector.
The US Food and Drug Administration has logged more than 1,700 adverse-event reports linked to compounded versions of semaglutide and tirzepatide, underscoring the scale of a booming market for copycat obesity medicines that remains under intense regulatory scrutiny. In an alert updated this year, the agency said it had received 990 reports involving compounded semaglutide and more than 730 involving compounded tirzepatide as of 31 May 2026, while warning that the true figure is likely higher because state-licensed pharmacies that are not outsourcing facilities are not required to report such events.
The FDA has said many of the reported incidents appear consistent with the side-effects seen in approved versions of these medicines, but a substantial share involve dosing mistakes. Those errors have included patients mismeasuring injections and clinicians calculating doses incorrectly, with some cases leading to hospital treatment. The agency has also warned about compounded semaglutide made with salt forms such as semaglutide sodium and semaglutide acetate, saying their safety and effectiveness have not been established and that it is not aware of any lawful basis for using them in compounding.
The rise in reports comes after a rapid expansion in the compounded GLP-1 market, fuelled by shortages that gave pharmacies a temporary legal pathway to produce versions of medicines still under patent protection. The FDA added Wegovy to its shortage list in March 2022, Ozempic in August 2022 and tirzepatide in December 2022, but later said the tirzepatide shortage ended in December 2024 and the semaglutide shortage in February 2025. The last enforcement-discretion window closed on 22 May 2025, after which the agency stepped up enforcement action against online sellers and marketers.
That crackdown has already touched companies operating at the centre of the market. Reuters reported in April that the FDA had issued a February warning letter to MEDVi, alleging that the company’s branding obscured the true source of its compounded semaglutide and tirzepatide products and falsely suggested they were equivalent to FDA-approved medicines. MEDVi said it never received the letter and argued it was aimed at an affiliate, although archived website material indicated that prospective customers were funnelled into MEDVi’s intake system and that its own terms named MEDVi LLC as the contracting party.
The regulatory pressure lands in a market that has proved highly lucrative. A study in JAMA Health Forum described the post-shortage market for compounded GLP-1s as robust, while Novo Nordisk estimated in January that as many as 1.5 million Americans were still using such products. Separate reporting has pointed to strong revenues at large compounders, and bankers cited by Bloomberg have estimated the category could be generating as much as $1 billion a year for pharmacies. At the same time, manufacturers and trade groups are fighting over the future of compounding in court and in Congress, where the bipartisan SAFE Drugs Act of 2025 remains under consideration.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
