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Research guide

Retatrutide vs Cagrilintide: two different research paths

Evidence checked 16 October 2026

These two peptides make an interesting comparison because they start with different ideas. Retatrutide is designed to activate three hormone-receptor types in one molecule. (Retatrutide study, NEJM (2023)) Cagrilintide follows the amylin pathway: amylin is a natural hormone made in the pancreas that helps signal fullness. (Cagrilintide study, The Lancet (2021))

Here is the simple version: they are different molecules, not two names for the same thing. This guide explains the distinction, the studies behind it and where CagriSema fits in.

The short answer

At a glance

The basic idea

Retatrutide
One molecule designed to activate three types of hormone receptor.
Cagrilintide
A long-acting molecule modelled on the natural hormone amylin.

(Retatrutide study, NEJM (2023)) (Cagrilintide study, The Lancet (2021))

Signals being studied

Retatrutide
GIP, GLP-1 and glucagon receptors.
Cagrilintide
Amylin-related signalling, including amylin and calcitonin receptors.

(Retatrutide study, NEJM (2023)) (Amylin research review (2026))

Is semaglutide part of it?

Retatrutide
No. Retatrutide is a separate molecule, not a semaglutide mixture.
Cagrilintide
Not in cagrilintide alone. CagriSema is the separate combination of cagrilintide and semaglutide.

(Retatrutide study, NEJM (2023)) (REDEFINE-1, NEJM (2025))

Human research to know

Retatrutide
The phase 3 TRIUMPH-1 trial studied 2,339 adults over 80 weeks.
Cagrilintide
An early human study tested cagrilintide alone; REDEFINE-1 also included a cagrilintide-only group alongside the combination.

(TRIUMPH-1, NEJM (2026)) (Cagrilintide study, The Lancet (2021)) (REDEFINE-1, NEJM (2025))

Why scientists are interested

Retatrutide brings three receptor targets into a single design. A receptor is a receiving point for a signal; an agonist is something that activates it. That is what “triple receptor agonist” means here. (Retatrutide study, NEJM (2023))

Cagrilintide explores a different route. It is based on amylin, rather than being another name for a GLP-1 medicine. (Cagrilintide study, The Lancet (2021)) Researchers have studied it on its own and with semaglutide, allowing them to examine the two components separately as well as together. (REDEFINE-1, NEJM (2025))

Both research paths have reached human trials. That gives readers published experiments to examine, not just a theory about how a molecule might work. (TRIUMPH-1, NEJM (2026)) (Cagrilintide study, The Lancet (2021))

Cagrilintide is not the same as CagriSema

This is the name difference worth remembering. Cagrilintide is one component; CagriSema combines it with semaglutide. (REDEFINE-1, NEJM (2025)) A headline about the combination therefore does not describe cagrilintide alone.

REDEFINE-1 made that distinction explicit: it included four groups, studying CagriSema, semaglutide alone, cagrilintide alone and placebo. (REDEFINE-1, NEJM (2025)) Checking which group a result comes from is a simple way to read the research more accurately.

Three studies that help explain the story

  • Cagrilintide early trial, 2021

    This study involved 906 adults without diabetes in total. Cagrilintide was compared with liraglutide and a placebo (a dummy treatment) over 26 weeks. Novo Nordisk funded the study. (Cagrilintide study, The Lancet (2021))

  • REDEFINE-1, 2025

    This 68-week trial involved 3,417 adults without diabetes. Its four groups helped distinguish the combination from its individual components. Novo Nordisk funded the study. (REDEFINE-1, NEJM (2025))

  • Retatrutide TRIUMPH-1, 2026

    This 80-week trial involved 2,339 adults with obesity and without diabetes. Researchers compared retatrutide with placebo and also examined knee-pain and sleep-apnoea outcomes in relevant participant groups. Eli Lilly funded the study. (TRIUMPH-1, NEJM (2026))

What these comparisons can tell us

These papers offer a useful view of two different research approaches, but they are not one direct retatrutide-versus-cagrilintide trial. Their participants, comparison groups and treatment periods differ. (Cagrilintide study, The Lancet (2021)) (REDEFINE-1, NEJM (2025)) (TRIUMPH-1, NEJM (2026)) A fair comparison keeps those differences visible rather than choosing a winner from separate headlines.

Safety is part of the evidence too. Stomach-related side effects, including nausea and other digestive symptoms, feature in the cited research. (Cagrilintide study, The Lancet (2021)) (REDEFINE-1, NEJM (2025)) (TRIUMPH-1, NEJM (2026)) The earlier retatrutide phase 2 paper also reported increases in heart rate. (Retatrutide study, NEJM (2023))

A published trial is not the same as medicine approval. The TGA identifies retatrutide as an unapproved therapeutic good and explains that unapproved goods cannot be advertised unless exempt. (TGA research and approval context) A research-use label should not be read as proof of approval.

For the related comparison, read Retatrutide vs Tirzepatide vs Semaglutide.

This guide summarises research, not recommendations for personal use. It provides no dosing, switching, combining or administration instructions. Trial findings do not establish the quality or medical suitability of a separately supplied research-labelled product.