CagriSema: the amylin + GLP-1 combo and what REDEFINE actually showed (2026)

The short version

CagriSema (Novo Nordisk) is an investigational once-weekly injectable that combines semaglutide (a GLP-1 drug) with cagrilintide (an amylin analog). In its phase 3 REDEFINE 1 trial it produced about 20% average weight loss at 68 weeks — in the same top tier as tirzepatide. It is not approved and cannot be prescribed. This explains the real evidence, the new amylin mechanism, and how it fits among the next-generation obesity drugs.

A different mechanism: amylin, not GIP or glucagon

The next-generation obesity drugs are distinguished by which hormone pathways they combine. Semaglutide uses GLP-1 alone. Tirzepatide adds GIP. Retatrutide adds GIP and glucagon. CagriSema takes a genuinely different route: it pairs GLP-1 (semaglutide) with amylin (cagrilintide) [1].

That matters because it opens a fourth mechanistic lane. Where tirzepatide and retatrutide build on the incretin hormones (GIP, glucagon), CagriSema brings in amylin — a separate satiety hormone with its own receptor and its own way of telling the brain you're full. Validating amylin as a target doesn't just give us one new drug; it suggests a whole additional axis that future combinations could exploit.

What amylin does, and why pairing it with GLP-1 works

Amylin is a hormone the pancreas co-secretes with insulin after you eat. Its job is to signal satiety: it slows gastric emptying, curbs the release of glucagon after meals, and acts on the brainstem to reduce food intake and produce a sense of fullness. It overlaps with GLP-1 in some effects but works through distinct receptors and brain circuits [1].

Cagrilintide is a long-acting, once-weekly version of that hormone, engineered to last long enough to pair with weekly semaglutide. The logic of the combination is that two different satiety signals, hitting the brain through two different pathways, suppress appetite more completely than either alone — and REDEFINE 1 tested exactly that by including semaglutide-only and cagrilintide-only arms alongside the combination [1].

What REDEFINE 1 showed

REDEFINE 1 was a phase 3a, 68-week, double-blind, placebo- and active-controlled trial of 3,417 adults with obesity (or overweight plus a complication) and without diabetes. It compared CagriSema against semaglutide alone, cagrilintide alone, and placebo — a design that isolates how much the combination adds over its parts [1].

CagriSema produced an estimated 20.4% mean body-weight reduction at 68 weeks, versus 3.0% with placebo — a difference of 17.3 percentage points (P<0.001). Participants were far more likely than placebo to reach the 5%, 20%, 25%, and 30% weight-loss thresholds, and the combination outperformed either semaglutide alone or cagrilintide alone — confirming that the two hormones together do more than either by itself [1].

How it compares with the other next-gen drugs

Line the pivotal figures up — remembering these are separate trials, not head-to-head — and CagriSema lands firmly in the top tier. Semaglutide 2.4 mg (Wegovy) reached about 14.9% in STEP-1 [3]. Tirzepatide 15 mg (Zepbound) reached about 20.9% in SURMOUNT-1 [2]. CagriSema reached 20.4% in REDEFINE 1 [1]. The investigational triple-agonist retatrutide posted the highest early figure at ~24% in phase 2.

So CagriSema is essentially neck-and-neck with tirzepatide and clearly ahead of semaglutide alone — but its real significance is the mechanism, not a marginally different percentage. By proving amylin works, it widens the field of what obesity drugs can target, and it makes head-to-head and combination studies the next interesting question rather than a simple 'which number is biggest' race.

Safety and tolerability

The side-effect profile was the familiar GLP-1 pattern, driven by the gastrointestinal system: nausea, vomiting, diarrhea, constipation, and abdominal pain affected 79.6% of the CagriSema group versus 39.9% on placebo, but these were mainly transient and mild to moderate [1]. That high GI rate is typical for a potent dual-agonist at trial doses; slow dose escalation is the standard way to blunt it in practice.

As with every drug still in development, phase 3 data — even from 3,417 people — is not large or long enough to characterize rare or long-term risks. That is one of the reasons a drug this effective still has to complete its full program and FDA review before it can be prescribed.

Status and what to do now

CagriSema is investigational. The REDEFINE phase 3 program (obesity and type 2 diabetes) is published, and Novo Nordisk has pursued regulatory approval, but it is not FDA-approved and cannot be prescribed as of 2026 [1]. Watch for regulatory decisions rather than a marketed product, and avoid any online source claiming to sell it — unapproved drugs cannot be verified for identity, dose, or purity.

If you want treatment now and qualify, the approved, evidence-based options are semaglutide (Wegovy) and tirzepatide (Zepbound) under a clinician's care. CagriSema is one more sign that the obesity-drug field is moving fast — with retatrutide and the oral orforglipron close behind — which is a reason to start an approved treatment now, not to wait for a drug that is still years from the pharmacy.