Lilly warns of unknown safety risks in tirzepatide-B12 compounded drugs

Eli Lilly issued a public warning about potential patient safety risks from compounded tirzepatide mixed with vitamin B12, including a newly identified impurity with unknown short- and long-term effects. The company says these compounded tirzepatide-B12 products lack safety monitoring and adverse-event reporting, has alerted the FDA, and urges patients to discuss alternatives with their physicians. Lilly also cautions about broader safety issues and contaminants in other unregulated tirzepatide knockoffs and calls for regulator action to curb mass compounding in favor of FDA-approved therapies like Mounjaro and Zepbound.