Cagrilintide vs Semaglutide

TL;DR

- Cagrilintide is a long-acting amylin analog. Semaglutide is a GLP-1 receptor agonist. They act on different pathways, which is why researchers combine them (Lau et al., 2021; Wilding et al., 2021). - In a phase 2 trial in type 2 diabetes, cagrilintide monotherapy reported about 8.1 percent weight reduction, semaglutide about 5.1 percent, and the combination (CagriSema) about 15.6 percent (Frias et al., 2023). - In the STEP 1 obesity trial, semaglutide reported about 15 percent mean weight loss over 68 weeks (Wilding et al., 2021). - Both are once-weekly by half-life design. The most reported side effects for both classes are gastrointestinal: nausea, vomiting, and diarrhea (Frias et al., 2023). - None of this is dosing guidance. Trial-reported ranges belong with a qualified clinician, not a self-directed plan.

What is the core difference between cagrilintide and semaglutide?

Cagrilintide mimics amylin, while semaglutide mimics GLP-1, so the two hit separate appetite-signaling systems.

Amylin is a hormone co-released with insulin from pancreatic beta cells. It slows gastric emptying and signals fullness through the brainstem. Cagrilintide is an engineered amylin analog built to last long enough for once-weekly use (Lau et al., 2021).

GLP-1 (glucagon-like peptide 1) is an incretin hormone released from the gut after eating. It boosts insulin release, lowers glucagon, slows gastric emptying, and reduces appetite through central pathways. Semaglutide is a GLP-1 receptor agonist and is the molecule studied in the STEP 1 obesity program (Wilding et al., 2021).

Because amylin and GLP-1 work through partly separate circuits, combining an amylin analog with a GLP-1 agonist is the logic behind CagriSema, the fixed-combination candidate that pairs cagrilintide with semaglutide (Frias et al., 2023).

How do the trial-reported weight numbers compare?

In a phase 2 type 2 diabetes trial, the combination reported roughly triple the weight reduction of semaglutide alone.

The figures below come from named trials. They describe what participants experienced in controlled research, not a promise of any personal result.

Two notes matter. First, the Frias et al., 2023 trial enrolled people with type 2 diabetes, and weight loss in diabetes populations often runs lower than in obesity-only populations, which is one reason semaglutide's 5.1 percent in that trial sits below the roughly 15 percent seen in STEP 1 (Wilding et al., 2021). Second, the combination number in Frias et al., 2023 exceeds the sum you might expect from either agent alone, which is the finding that pushed CagriSema into later-stage study.

How do their half-lives and dosing schedules compare?

Both are engineered for once-weekly administration, so their circulating half-lives are measured in days, not hours.

Cagrilintide was designed as a long-acting amylin analog suitable for once-weekly dosing (Lau et al., 2021). Semaglutide's long half-life likewise supports a once-weekly schedule and is the basis for the weekly regimen used across the STEP program (Wilding et al., 2021).

In the combination studies, participants received both molecules on a shared weekly schedule (Frias et al., 2023). Exact titration steps used in each trial are reported in those papers. Any personal schedule is a clinical decision, and this page does not set one.

What are the reported side effects of each?

Gastrointestinal effects dominate for both, which is expected given both slow gastric emptying.

In the phase 2 combination trial, nausea, vomiting, and diarrhea were the most commonly reported adverse events, and they were generally described as mild to moderate (Frias et al., 2023). The STEP 1 semaglutide trial reported a similar pattern, with gastrointestinal complaints the leading reason participants adjusted therapy (Wilding et al., 2021).

Because the combination stacks two appetite-suppressing mechanisms, the tolerability profile is an active area of study rather than a settled question. This is one more reason personal use belongs with a clinician who can monitor response.

Why combine them instead of using one?

The pairing targets two appetite pathways at once, and the phase 2 data suggest the effects add up.

Amylin signaling (cagrilintide) and GLP-1 signaling (semaglutide) reach the brain through partly distinct routes. Frias et al., 2023 reported that the combination reached about 15.6 percent weight reduction versus about 5.1 percent for semaglutide alone in the same trial, a gap large enough to justify combined development. The trade-off is that layering mechanisms can also layer side effects, which is why the tolerability data are watched closely (Frias et al., 2023).