Research Evidence
Tirzepatide has one of the most robust clinical trial programs of any peptide therapeutic, with multiple large-scale Phase 3 trials establishing its efficacy and safety profile.
SURPASS-2 Trial: A head-to-head comparison against semaglutide 1 mg weekly in patients with type 2 diabetes. Tirzepatide at all three doses (5 mg, 10 mg, 15 mg) demonstrated statistically superior HbA1c reductions and weight loss compared to semaglutide 1 mg. This trial established tirzepatide's superiority over the leading GLP-1 monotherapy.
SURMOUNT-1 Trial: The landmark obesity trial in non-diabetic adults with BMI ≥30 (or ≥27 with weight-related comorbidity) at 72 weeks (trial product estimand, as published in NEJM):
- 5 mg dose: 16.0% weight reduction
- 10 mg dose: 21.4% weight reduction
- 15 mg dose: 22.5% weight reduction
- Placebo: 3.1% weight reduction
- 57% of participants on 15 mg achieved ≥20% weight loss (primary published benchmark); a secondary/post-hoc analysis reported 36% achieving ≥25% weight loss
SURMOUNT-2 Trial: In adults with obesity and type 2 diabetes at 72 weeks, tirzepatide demonstrated 12.8%–14.7% weight loss with significant improvements in glycemic control, demonstrating efficacy in a more metabolically compromised population.
SURPASS-1 Trial: In treatment-naive type 2 diabetes patients, tirzepatide monotherapy produced HbA1c reductions of 1.87%–2.07% versus 0.04% for placebo, with all doses achieving HbA1c targets below 7%.
SURMOUNT-4 Trial: Examined weight regain after discontinuation. Participants who lost weight on tirzepatide regained approximately two-thirds of their lost weight within one year of stopping, underscoring the chronic nature of obesity treatment.