CagriSema and tirzepatide represent two different bets on how to improve on first-generation GLP-1 drugs like semaglutide. Tirzepatide, sold as Zepbound and Mounjaro, adds a second incretin mechanism, a GIP receptor agonist, to a GLP-1 backbone. CagriSema, Novo Nordisk's combination of cagrilintide and semaglutide, instead pairs semaglutide's GLP-1 activity with cagrilintide, an amylin receptor agonist that works through an entirely separate hormone pathway. A head-to-head trial, REDEFINE 4, gives a direct comparison of how those two strategies actually perform against each other.

What REDEFINE 4 Found

REDEFINE 4 was an 84-week trial enrolling 809 adults with obesity and at least one weight-related health condition, with an average starting weight of 114.2 kg. Results announced February 23, 2026 showed CagriSema produced 23% weight loss on an intent-to-treat basis, compared with 25.5% for tirzepatide at its highest dose. When the analysis was adjusted for how consistently participants stayed on their assigned treatment, the gap was similar: 20.2% for CagriSema versus 23.6% for tirzepatide.

Why CagriSema "Failed" a Trial It Arguably Still Did Well In

The REDEFINE 4 trial's formal primary endpoint was demonstrating that CagriSema was noninferior to tirzepatide, meaning statistically not meaningfully worse. CagriSema did not meet that bar; the roughly 2.5-percentage-point gap in weight loss exceeded the noninferiority margin the trial had been designed around. It's worth separating that statistical outcome from the plain-language result: 23% average weight loss is still substantial by the standards of any obesity drug trial run before the current generation of incretin therapies, and CagriSema clearly worked. It simply didn't work quite as well as tirzepatide did in this specific comparison, and the trial was designed with strict enough statistical requirements to formally register that gap as a "failed" endpoint rather than a rounding difference.

Mechanism Differences That May Explain the Gap

Tirzepatide's dual GLP-1/GIP mechanism and CagriSema's GLP-1/amylin mechanism both build on top of a semaglutide-like GLP-1 backbone, but GIP and amylin affect appetite and metabolism through different downstream pathways, and it's not established in the research to date that one approach is inherently superior to the other across all patients. This site's explainer on amylin agonists like cagrilintide covers the mechanism in more depth. Individual response to GLP-1-based therapies already varies considerably from patient to patient, and head-to-head averages like these describe typical outcomes across a trial population, not a guarantee for any specific person.

Regulatory Status

Tirzepatide is FDA-approved as Zepbound for chronic weight management and as Mounjaro for type 2 diabetes. CagriSema, as of this writing, is not yet FDA-approved and remains under regulatory review based on its completed trial program, of which REDEFINE 4 is one part.

The Bottom Line

Based on REDEFINE 4, tirzepatide currently holds a modest but statistically meaningful edge over CagriSema in head-to-head weight loss, though CagriSema's own results remain substantial in absolute terms. Neither result should be read as a verdict on which mechanism, dual incretin or GLP-1-amylin, is the better overall strategy going forward, since multiple companies are still running trials on new combinations, including the eloralintide-tirzepatide pairing covered elsewhere on this site. Anyone weighing treatment options between these drug classes should discuss the specifics, including side-effect profiles that a single weight-loss percentage doesn't capture, with a licensed physician.