Tirzepatide vs. Dulaglutide as Weight Loss Drugs

Efficacy Level of Both Drugs 

Research studies directly comparing the efficacy of tirzepatide versus dulaglutide that can be generalized to the US population are still needed to fully understand how these two medications differ in their ability to lower patients’ hemoglobin A1c and promote weight loss. 

However, studies exist comparing tirzepatide to a drug similar to dulaglutide, semaglutide. In a randomized trial published in the New England Journal of Medicine, 1,879 adult patients with type 2 diabetes were assigned to once-weekly injections of either tirzepatide (at 5 mg, 10 mg, or 15 mg) or semaglutide 1 mg for 40 weeks. 

They found that patients on tirzepatide at all three doses had a larger improvement in their hemoglobin A1c and a bigger reduction in body weight. For example, the tirzepatide 15 mg group lost 11.2 kg, versus the semaglutide group, who lost 5.7 kg. That is nearly a 2x difference! Even at the lowest dosage, tirzepatide was found to be superior for both outcome measures. 

A 2018 review article comparing GLP-1 receptor agonists reported that, in studies, semaglutide 1 mg once weekly resulted in a mean weight loss from 4.53 to 6.5 kg, while dulaglutide at 1.5 mg once weekly resulted in a mean weight loss from 0.87 to 3.03 kg. With the results of these two studies, we can extrapolate that tirzepatide may lead to greater weight loss than dulaglutide.