Zepbound vs Wegovy: Eli Lilly’s weight-loss drug shows stronger results in new global trial
If you’ve been tracking the global development of weight-loss medications, you’ve likely come across Wegovy by Danish pharma giant Novo Nordisk and Zepbound from U.S.-based Eli Lilly. According to a recent study unveiled at the European Congress on Obesity in Spain, Zepbound has demonstrated superior results in helping people lose weight and reduce abdominal fat compared to Wegovy, Bloomberg reported.
What did the clinical trial find?
In a direct comparison funded by Eli Lilly, Zepbound (tirzepatide) significantly outperformed Wegovy (semaglutide) in several critical weight-loss metrics over a 72-week period. Both medications are part of a new class of drugs designed to treat type 2 diabetes and obesity.
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Tirzepatide acts as a dual agonist of GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1) receptors.
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Semaglutide, on the other hand, targets only the GLP-1 receptor.
The trial revealed that participants taking Zepbound lost an average of 47% more weight than those on Wegovy. In terms of waistline reduction, the Zepbound group lost around 18.4 cm, compared to 13 cm in the Wegovy group—translating to nearly 2 extra inches off the waist.
Why does waist size matter?
A shrinking waistline isn’t just about physical appearance—it’s a major health indicator. Waist circumference reflects the amount of visceral fat—the fat that surrounds internal organs and is associated with serious conditions such as:
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Cardiovascular disease
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Type 2 diabetes
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Fatty liver disease
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Stroke
Dr. Louis Aronne, lead investigator of the study and professor at Weill Cornell Medicine, emphasized that even a 2-inch waist reduction can significantly improve blood pressure and other metabolic health parameters.
How much weight did participants actually lose?
The participants had an average starting weight of 113 kg (about 249 pounds). Results showed:
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Zepbound: A majority lost at least 10% of their body weight, and twice as many reached a 25% reduction compared to the Wegovy group.
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Wegovy: Around 60% of users achieved at least 10% weight loss.
Researchers described these outcomes as clinically meaningful, with the potential to dramatically lower risks of chronic diseases.
What about side effects?
Both treatments presented similar mild to moderate side effects, mostly during the early phase of use:
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Zepbound users more frequently reported injection site reactions, such as pain or swelling.
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Wegovy had a slightly higher dropout rate due to nausea, vomiting, or other gastrointestinal symptoms.
