SURMOUNT-5 is the first major head-to-head study comparing Tirzepatide (Mounjaro®) with Semaglutide (Wegovy®) in adults with obesity. It's the scientific basis for why Lunaris Clinics chooses Tirzepatide.
SURMOUNT-5 is a randomised, controlled phase 3b study that directly compared tirzepatide with semaglutide in adults with obesity (BMI ≥ 30) without type 2 diabetes — or overweight (BMI ≥ 27) with at least one weight-related condition.
Participants were randomised 1:1 across two arms: one with tirzepatide (titrated up to a maximum tolerated dose: 10 mg, 12.5 mg or 15 mg per week) and one with semaglutide (titrated up to a maximum tolerated dose: 1.7 mg or 2.4 mg per week). The primary endpoint was the percentage change in weight from baseline at 72 weeks.
After 72 weeks, researchers saw a statistically significant difference in average weight loss between the two arms.
Difference: about 6.5 percentage points more weight loss with tirzepatide. The difference was statistically significant (P < 0.001).
At every threshold (≥10%, ≥15%, ≥20%, ≥25% weight loss), significantly more participants in the tirzepatide arm reached the goal:
The percentages above are rounded approximations based on the published results. For exact intent-to-treat and per-protocol analyses, please refer to the original publication.
In SURMOUNT-5, the overall safety profile between the two medicines was comparable. The most common side effects in both arms were gastrointestinal in nature.
In SURMOUNT-5, the proportion of participants stopping treatment due to side effects was relatively low and comparable between both arms.
Based on SURMOUNT-5 and supporting research, Lunaris Clinics has chosen Tirzepatide as our first-line medicine in weight treatment. That doesn't mean semaglutide is unsafe or ineffective — both are approved, working medicines — but in this head-to-head study, tirzepatide was superior in terms of weight reduction.
During your intake we'll look together at which medicine fits best with your medical situation, history and goal.
SURMOUNT-5 isn't the only study our choice rests on. Tirzepatide (Mounjaro®) has been studied since 2022 in an extensive clinical trial programme — for both obesity and type 2 diabetes.
First major phase 3 study: ~2,500 adults with obesity, 72 weeks of treatment. Tirzepatide 15 mg led to an average ~22.5% weight loss — versus ~2.4% on placebo. Jastreboff AM, Aronne LJ et al.
~940 adults with obesity and type 2 diabetes, 72 weeks. Tirzepatide 15 mg led to ~15.7% weight loss — a combination that's been hard to treat before. Garvey WT, Frias JP et al.
Looked at how much extra weight loss tirzepatide adds after 12 weeks of intensive lifestyle changes. Result: ~21.1% on top of weight already lost. Wadden TA et al.
What happens when you stop? Those who kept taking tirzepatide held on to their weight loss; the placebo group put weight back on. Shows it's not a short-term fix. Aronne LJ, Sattar N et al.
Two trials in adults with obesity and obstructive sleep apnea. Tirzepatide significantly reduced the apnea–hypopnea index — an important comorbidity of obesity. Malhotra A et al.
Six-part study series comparing tirzepatide with placebo, semaglutide, insulin degludec and insulin glargine. Significant reductions in HbA1c and weight across all comparisons.
Together these trials form the scientific foundation behind Tirzepatide: consistent, clinically meaningful weight reduction across different patient groups, with a predictable side-effect profile and proven maintenance with continued use.
The SURMOUNT-5 study in patient-friendly language: key results, study design, safety profile and what it means for your treatment. In Lunaris house style, free to download. (PDF in Dutch.)
The publications and sources below form the basis for the information on this page.
Our GP is happy to answer your questions about Tirzepatide, the SURMOUNT-5 results, or how a treatment would work for you in practice.
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