Zepbound vs. Wegovy: The Head-to-Head Data Is Finally Here
The wait is over. The SURMOUNT-5 trial results are in, and they answer the question my patients ask me every week: “Which one is better?” For tirzepatide (Zepbound) and semaglutide (Wegovy), the full dataset published in The New England Journal of Medicine gives us an unambiguous answer.
In a 72-week head-to-head trial of 751 adults with obesity, tirzepatide produced a mean weight reduction of 20.2% versus 13.7% for semaglutide. That’s about 47% more relative weight loss for the dual GIP/GLP-1 agonist over the GLP-1 mono agonist. For a representative patient, that translated to 50.3 lbs versus 33.1 lbs. The superiority held across all secondary endpoints too.
Looking at the clinically meaningful responses: 31.6% of tirzepatide participants lost 25% or more of their body weight, compared to 16.1% on semaglutide. And 81.6% of tirzepatide users hit at least 10% weight loss versus 60.5% on semaglutide. Waist circumference dropped 18.4 cm versus 13.0 cm — a meaningful difference in central fat. Both drugs were well tolerated; tirzepatide actually had a lower discontinuation rate due to adverse events (6.1% vs 8.0%), with primarily mild-to-moderate GI side effects.
What This Means for Denver Patients
If you’re on Wegovy and not hitting your weight loss goals, these data support a conversation with your physician about whether tirzepatide is right for you. Nearly 90% of participants reached the maximum 15 mg tirzepatide dose, so tolerability at full dose is achievable for most.
For Greenwood Village and Denver metro patients specifically, the insurance picture is worth noting. Both agents are increasingly covered, but formulary preference varies by plan. That individual detail — your insurance, your comorbidities, your side effect history — is where clinical guidance beats a one-size-fits-all answer. That’s also where ongoing care with a physician who actually knows your chart matters.
The head-to-head data is now settled science. The question of which is better for you is still a conversation worth having with your physician, not a telehealth algorithm.
For those on Wegovy who are below target, transitioning to tirzepatide under physician supervision is now supported by the strongest comparative data we have. For those starting fresh, these results give us a clearer evidence baseline to set expectations.
I discuss GLP-1 options with patients at Clinical Nutrition Center in Greenwood Village every week. Book a consult if you’d like an evidence-based opinion tailored to your situation.
Research Brief | Dr. Ethan Lazarus, MD | Clinical Nutrition Center | July 27, 2026