Semaglutide vs. Tirzepatide: Which is Better for Weight Loss?
The battle of the GLP-1 agonists. We break down the clinical data from the STEP 1 and SURMOUNT-1 trials to see which medication reigns supreme.
Semaglutide
Ozempic®, Wegovy®
A pure GLP-1 receptor agonist. It mimics a hormone that targets areas of the brain that regulate appetite and food intake.
Tirzepatide
Mounjaro®, Zepbound®
A dual agonist targeting both GLP-1 and GIP receptors. This "synergistic" effect leads to potentially greater weight reduction.
The Clinical Trials: What the Data Says
To understand which is "better," we look at the pivotal clinical trials that led to their FDA approvals.
STEP 1 Trial (Semaglutide)
In the STEP 1 trial, participants taking 2.4 mg of semaglutide weekly lost an average of 14.9% of their body weight over 68 weeks, compared to just 2.4% in the placebo group.
SURMOUNT-1 Trial (Tirzepatide)
The SURMOUNT-1 trial tested tirzepatide at various doses. At the highest dose (15 mg), participants achieved an average weight loss of 20.9% over 72 weeks.
Key Takeaway
While both medications are highly effective, Tirzepatide acts on two hormonal pathways instead of one, which clinical data suggests leads to greater total weight loss on average.
Visualize the Difference
What does a 15% loss look like compared to a 21% loss? For a 200 lb person, that's a difference of 12 lbs (30 lbs vs 42 lbs lost).
Seeing the difference on your own body can help you set realistic expectations.