Tirzepatide (Mounjaro) is FDA-approved for lowering blood sugar in people with type 2 diabetes by activating clocose-dependent insulinotropic polypeptide (GIP) and glucagon-like polypeptide (GLP-1) receptors. It increases insulin production and lowers the amount of blood sugar produced in the liver.

In clinical trials, weight loss was a significant side-effect. Tirzepatide is not FDA-approved for weight loss but is used to treat overweight and obesity in adults, along with diet and exercise. Phase 3 clinical trials are currently underway to evaluate Tirzepatide’s weight loss potential, and Eli Lilly has received FDA Fast-Track designation for mounjaro.

In the SURMOUNT-1 clinical trial, average weight loss after 72 weeks was 15% for the 5 mg dose, 19.5% for the 10 mg dose, and 20.9% for the 15 mg dose.

SURPASS-2 clinical trial, a 40 week noninferiority trial comparing Mounjaro vs. Ozempic (+ metformin), reductions in body weight were greater with tirzepatide than with semaglutide (least-squares mean estimated treatment difference, -1.9 kg, -3.6 kg, and -5.5 kg, respectively; P<0.001 for all comparisons). The mean change in weight was 8.2% at the 5 mg dose, 10% at the 10 mg dose, and 11.8% at the 15 mg dose, compared with Ozempic’s 6.2% at the 1 mg dose.