Your Off-Brand GLP-1 Is Dirtier Than You Think

Trying to get a bargain on your GLP-1 medication might come with some added danger. Compounded copycats of the blockbuster drug tirzepatide, the active ingredient in Mounjaro and Zepbound, could possibly contain concerning byproducts. On Thursday, Eli Lilly, the maker of tirzepatide, issued a warning to the public. The company claims to have identified “significant levels of an impurity” in compounded drugs that combine tirzepatide with vitamin B12. Health authorities have previously advised people to stay away from these customized versions of GLP-1s. “People receiving tirzepatide-B12 products from compounders, telehealth companies, medspas, or anyone else should be aware that they may be using a potentially dangerous product with unknown risks,” the company stated. Compounded drugs are custom-made formulations of existing medications that can be produced by pharmacies under certain circumstances. For a time, pharmacies were given wider latitude to make GLP-1 drugs like semaglutide (Ozempic and Wegovy) and tirzepatide that were in shortage. People haven’t flocked to compounded GLP-1s just because they’re available. They’ve also been substantially cheaper out of pocket than the off

Mar 12, 2026 → Apr 1, 2026