Eli Lilly Warns of Impurities in Compounded Tirzepatide Mixed with Vitamin B12

U.S. drugmaker Eli Lilly has warned against compounded versions of its weight-loss and diabetes drug tirzepatide mixed with vitamin B12, after laboratory tests detected significant impurities caused by a chemical reaction between the two. The company highlighted unknown short- and long-term health effects of these impurities and emphasized that compounded drugs are not FDA-approved. Lilly has taken legal action against compounders marketing such products, which they argue are made under a federal provision for personalized medication, though the safety and efficacy remain unverified.