Cagrilintide: The Amylin Peptide Behind CagriSema — Evidence & FDA Status

Cagrilintide is not a GLP-1 drug, even though it's almost always mentioned in the same breath as semaglutide and tirzepatide. It works on a different hormone system entirely, it has real Phase 3 human trial data behind it, and as of this writing it has never been approved by the FDA on its own — its regulatory path runs entirely through a fixed-dose combination product, CagriSema, that Novo Nordisk filed for approval in December 2025. This article separates what cagrilintide's own trials actually measured from what "CagriSema" the combination product showed, because the marketing around this molecule blends the two constantly.

What Cagrilintide Actually Is

Cagrilintide is a long-acting analog of amylin, a hormone your pancreas co-secretes with insulin after meals. Amylin and GLP-1 act on different receptors and through complementary mechanisms — amylin slows gastric emptying and increases satiety signaling in the brainstem, rather than working through the incretin pathway GLP-1 drugs use. That's the pharmacological rationale for pairing cagrilintide with semaglutide: two non-redundant appetite-and-satiety mechanisms stacked together, rather than one drug pushed to a higher dose. It is administered as a once-weekly subcutaneous injection, structurally engineered (via fatty-acid acylation, the same trick used in semaglutide and liraglutide) for a long enough half-life to support weekly dosing.

For where cagrilintide fits against the rest of the fat-loss peptide field, see our guide to peptides for fat loss, and for the triple-agonist competing for the same "next big GLP-1" attention, see retatrutide for athletes and body recomposition.

The Monotherapy Data: What Cagrilintide Does Alone

Before it was ever paired with semaglutide, cagrilintide was tested by itself. A 26-week Phase 2 trial randomized 706 adults with obesity or overweight to one of five cagrilintide doses (0.3 to 4.5 mg weekly), to liraglutide 3.0 mg daily, or to placebo¹. Every cagrilintide dose beat placebo: mean weight reduction ranged from 6.0% to 10.8% across the dose range, versus 3.0% on placebo¹. At the top dose, cagrilintide 4.5 mg slightly outperformed liraglutide 3.0 mg — 10.8% versus 9.0% weight loss, a modest but statistically significant difference¹. Gastrointestinal adverse events (mainly nausea, constipation, diarrhea) occurred in 41–63% of cagrilintide recipients depending on dose, versus 32% on placebo, and 4% of participants discontinued permanently due to adverse events¹. That is a real, independently meaningful weight-loss effect from amylin-receptor agonism alone — not just an additive bonus riding on semaglutide's back.

A separate trial tested cagrilintide given alongside semaglutide 2.4 mg specifically to characterize safety, tolerability, and pharmacokinetics of the combination, rather than efficacy — establishing that the two drugs could be co-administered without an unexpected interaction, which is the regulatory groundwork the later efficacy trials built on².

CagriSema: The Combination Phase 3 Data

The Phase 3 program is where the "cagrilintide" story becomes, functionally, the "CagriSema" story — Novo Nordisk's fixed-dose combination of cagrilintide 2.4 mg and semaglutide 2.4 mg. REDEFINE 1, a 68-week, placebo-controlled trial in 3,417 adults with obesity or overweight, found the combination produced an estimated mean weight change of −20.4% versus −3.0% on placebo (a −17.3 percentage-point difference, p<0.001), with significantly more participants reaching 5%, 20%, 25%, and 30% weight-loss thresholds than on placebo³. That trial also included separate cagrilintide-alone and semaglutide-alone arms, letting the combination be judged against each component individually rather than only against placebo³. Gastrointestinal adverse events occurred in 79.6% of the combination group versus 39.9% on placebo, described as mainly transient and mild-to-moderate³.

REDEFINE 2, run in adults with obesity or overweight who also have type 2 diabetes, found a similar pattern — meaningful weight loss and glycemic improvement, with a comparable adverse-event profile to REDEFINE 1⁴. Novo Nordisk's own December 2025 filing announcement reported REDEFINE 1 achieving 91.9% of participants losing at least 5% of body weight versus 31.5% on placebo, alongside discontinuation for adverse events of 5.9% on CagriSema versus 3.5% on placebo, and specific GI rates of nausea (55% vs 12.6%), constipation (30.7% vs 11.6%), and vomiting (26.1% vs 4.1%)⁵.

FDA Status: Filed, Not Approved

As of this writing, cagrilintide has no FDA approval in any form — not as a standalone drug, and not yet as CagriSema. Novo Nordisk announced on December 18, 2025 that it had submitted a New Drug Application to the FDA for CagriSema, with review expected to run through 2026⁵. That is a real regulatory milestone — an NDA filing means the company believes its Phase 3 package is complete — but a filing is not a decision, and standard FDA review timelines run roughly 10–12 months from acceptance. Until a decision is issued, CagriSema is not a prescribable product in the United States, and cagrilintide has never had — and is not separately pursuing — approval as a standalone drug. Anything sold today as "cagrilintide" outside a clinical trial is unregulated research-market material, with no FDA oversight of its identity, purity, sterility, or labeled dose.

That gap between "real Phase 3 efficacy data" and "actually approved and legally prescribable" is the same gap covered in our guide to where to buy peptides and the research-chemical gray zone, and the purity question specifically is covered in how to verify a peptide's COA and third-party testing — worth reading before treating any vial labeled "cagrilintide" as equivalent to what REDEFINE 1 and 2 participants actually received under GMP manufacturing and clinical monitoring.

Bottom Line

Cagrilintide has genuine, replicated human efficacy data behind it — a real amylin-receptor weight-loss effect on its own, and a materially larger effect layered onto semaglutide in two Phase 3 trials. That's a stronger evidence base than most compounds covered on this site can claim. But it is still, as of this writing, an unapproved molecule: Novo Nordisk's FDA application for the CagriSema combination was filed in December 2025 and remained under review through 2026, cagrilintide has no independent approval pathway, and the gastrointestinal side-effect burden in every trial has been substantial (GI events in roughly 80% of the CagriSema arm in REDEFINE 1). Real trial evidence and "approved, prescribable, and manufactured under regulatory oversight" are two different claims — and for cagrilintide, only the first one is true today. It isn't the only investigational dual-mechanism peptide in this exact position, either — Boehringer Ingelheim's survodutide, a glucagon/GLP-1 dual agonist, has its own real Phase 2 efficacy data and its own notably high adverse-event rate, covered in survodutide: evidence and FDA status.