Cagrilintide is the second half of the drug most people have heard of as CagriSema. It is not a GLP-1 drug. It acts on the amylin receptor, a separate pathway involved in how full you feel after eating, and it is given as a weekly injection in its trials. What follows is what those trials measured, and what has not been shown. It sits under the weight goal.
A different receptor from the GLP-1 drugs
Amylin is a hormone released alongside insulin. Cagrilintide is built to act on its receptor, which is why it is usually paired with a GLP-1 drug rather than compared against one: the two act on different targets.
That pairing is the reason most cagrilintide evidence is really evidence about a combination. Both trials below test a fixed-dose combination of cagrilintide and semaglutide [1] [2]. Only one of them isolates cagrilintide on its own.
The same question comes up with the other molecule the FDA names in the same sentence, which is covered in what the retatrutide trials show. For the approved drugs these trials use as comparators, see tirzepatide vs semaglutide.
What the weight trial measured
REDEFINE 5 enrolled 331 adults across 21 sites in Japan and one in Taiwan [1]. Everyone had a BMI of at least 27 with two obesity-related complications, or at least 35 with one. Just under a quarter, 80 of 331, had type 2 diabetes.
Participants were assigned to weekly cagrilintide-semaglutide or to semaglutide alone, both escalated to 2.4 mg, for 68 weeks [1]. Mean weight change at week 68 was −18.4% on the combination against −11.9% on semaglutide alone, a difference of 6.5 percentage points (95% CI −8.4 to −4.6; p<0.0001).
Two limits are worth holding onto. The comparator was semaglutide, not placebo, so the trial shows what adding cagrilintide did rather than what either drug does from a standing start. And the population was east Asian, which the authors state was the point of the trial rather than an incidental feature.
The trial with a cagrilintide-only arm
REIMAGINE 2 randomized 2,713 people with inadequately controlled type 2 diabetes across 30 countries, all on metformin with or without an SGLT2 inhibitor [2]. Mean baseline HbA1c was 8.2%.
Its value here is one arm: 152 people received cagrilintide 2.4 mg on its own. That is the largest published group taking this molecule without semaglutide beside it, and it is small next to the 603 on the combination.
On the primary endpoint, HbA1c fell 1.91 percentage points on the combination against 1.75 on semaglutide 2.4 mg, a difference of 0.16 points (95% CI −0.27 to −0.05; p=0.0035)[2]. The gap is statistically clear and clinically narrow, and the authors frame the result as an added benefit rather than a replacement.
What the trials reported as side effects
Gastrointestinal effects were the most common in both trials [1] [2]. In REDEFINE 5 they were reported by 53% of the combination group and 51% of the semaglutide group, so adding cagrilintide moved that figure by about two percentage points.
Overall adverse event rates were close as well: 87% against 84% in REDEFINE 5, and 86.9% against 81.2% in REIMAGINE 2, with 70.5% on placebo [1] [2]. Discontinuation differed more than the event counts did, at 10% on the combination against 6% on semaglutide in REDEFINE 5.
One death occurred in the semaglutide 2.4 mg group of REDEFINE 5, which the investigator did not judge to be treatment related [1]. Neither trial was designed to measure long-term outcomes.
Can a pharmacy compound it?
No, and the FDA says so by name. Its page on unapproved GLP-1 drugs states that retatrutide and cagrilintide cannot be used in compounding under federal law, and that they are not components of FDA-approved drugs and have not been found safe and effective for any condition [3].
Cagrilintide is also named on no 503A bulk substances list [4]. Those two facts together mean there is no lawful route to a compounded cagrilintide in the United States, whatever a website offering one says.
What this means for you
If you are reading about cagrilintide because of the weight figures, the number to keep is the comparison, not the headline. The trial that produced 18.4% was measuring a combination against semaglutide alone, and the margin it added was 6.5 percentage points [1].
If you are reading because something is being sold to you, the relevant fact is the regulatory one. The molecule is in late-stage trials and is not available through a lawful compounding route [3]. Anything sold as it today sits outside the evidence described here.
For the wider question of what may lawfully be compounded and what may not, see are peptides legal. For the molecules in this space that do have human trials behind them, see peptides for weight loss.