Eli Lilly Blasts Use of Mounjaro and Zepbound for “Cosmetic Weight Loss”

The pharmaceutical giant behind the popular weight loss injectables Zepbound and Mounjaro is — ironically, perhaps — calling people out for using them to lose weight.

In an open letter, drugmaker Eli Lilly declared that it "stands against the use of its medicines for cosmetic weight loss" — even as people using the Ozempic competitors for that very purpose have made the company billions of dollars over the past few years.

Both Mounjaro and Zepbound, which use the hormone-mimicking drug tirzepatide as their active ingredient, are classified as weight loss medications for people with diabetes, high cholesterol or high blood sugar. Much like Ozempic, however, these drugs are often prescribed and taken off-label for weight loss even for those who don't have those conditions.

While doctors rush to prescribe their overweight patients these subcutaneously-injected drugs that can both suppress appetite and cause stomach issues, the company raking in the dough from those prescriptions is calling foul.

As Lilly notes in its warning letter, Mounjaro and Zepbound should only be used as per FDA approval — meaning exclusively for people who are both overweight and have another weight-related condition, like diabetes.

The Indianapolis-based company added that because tirzepatide has not been tested on people who have gastrointestinal disorders such as pancreatitis and gastroparesis, people who have those conditions should avoid the drug.

Though it didn't mention it by name, the specter of Denmark's Novo Nordisk, which makes the diabetes injection Ozempic and its weight loss sister drug Wegovy, hangs heavy over Lilly letter. The pharma firm cautioned that tirzepatide should not be taken by anyone under 18 and will never be advertised on social media — two issues that have become salient for Nordisk as unapproved ads for its products run online and as more and more children are being prescribed Ozempic and Wegovy.

The rival firms' interests dovetail towards the end of the open letter, where Lilly issued a stark warning about buying and using compounded tirzepatide from online pharmacies that are not regulated by the FDA. Nordisk, notably, has also had to deal with the same issue regarding compounded semaglutide, the active ingredient in Ozempic and Wegovy.

"Be aware that when you purchase products that are not FDA-approved medicines or obtain medicines from an unverified source or without a prescription from a licensed healthcare provider, you may be purchasing fake, counterfeit, or otherwise unsafe products," the letter cautioned.

It's an intriguing positioning for the pharma giant. Entire fields of treatment — think botox, or lip filler, or Brazilian butt lifts — have essentially no purpose except to address patients' cosmetic concerns about their bodies. Will drugs like semaglutide and tirzepatide chart a different course, with their makers positioning them as strictly medical? For now, that certainly feels like Lilly's strategy.

More on weight loss warnings: Scary Counterfeit Ozempic Contains the Wrong Drug