Overview

• At ENDO 2025 in San Francisco, University of Michigan researchers reported that tirzepatide produced roughly 20% reductions in body weight and fat mass in obese mice while slowing breast tumor growth.
• End-of-study measurements showed tumor volume was closely correlated with overall body weight, adipose depot weights, and liver fat content.
• Collaborative studies with the University of North Carolina at Chapel Hill are underway to distinguish the drug’s direct anti-tumor effects from its weight-loss benefits.
• As a dual GLP-1/GIP agonist, tirzepatide leverages appetite suppression and enhanced metabolic control, but its direct mechanisms in cancer inhibition remain to be clarified.
• Based on these preliminary findings, researchers are designing human trials to evaluate tirzepatide’s safety and efficacy in obesity-linked breast cancer therapy.