Cagrilintide: Uses, Benefits and Safety

Cagrilintide is an experimental once-weekly injection that reduces appetite through amylin, a hormone the pancreas releases alongside insulin after a meal. It is the only compound in serious late-stage development for obesity that does not work through the incretin receptors.

That distinction is the reason it matters. Every other drug in this field, from liraglutide to retatrutide, is a variation on the same GLP-1 theme. Cagrilintide arrives at the same destination by a different road, which is what makes combining it with a GLP-1 drug interesting rather than redundant.

Alone it produced about 11.5% average weight loss. Combined with semaglutide, as CagriSema, that reached 22.7%. It is not approved anywhere, and the honest summary of the evidence is that it is early rather than thin.

What is cagrilintide?#

Cagrilintide is a long-acting synthetic analogue of human amylin, given as a subcutaneous injection once a week. If the underlying vocabulary is unfamiliar, what peptides actually are covers it.

Where it comes from#

Amylin is co-secreted with insulin from the same pancreatic beta cells whenever a meal raises blood sugar. Human amylin is difficult to work with as a drug because it aggregates readily, which is why the first analogue, pramlintide, had to be modified and still required dosing at every meal.

Cagrilintide is engineered for stability and for a long half-life, with a fatty acid chain that binds it to albumin in the blood. That is the same trick semaglutide uses, applied to a different hormone.

Proposed mechanisms of action#

• Brainstem signalling. Amylin acts on receptors in the area postrema and nearby brainstem nuclei, which is a distinct site from where GLP-1 does most of its appetite work.
• Slowed gastric emptying. Food leaves the stomach more slowly, so fullness arrives sooner and persists.
• Reduced glucagon after meals. Less sugar released from the liver at the point it is least needed.

The practical consequence of the first point is what drives the CagriSema programme. Two appetite pathways, acting at different receptors, can be pushed at once without simply pushing one harder.

What cagrilintide is claimed to do#

Weight loss on its own#

The claim is meaningful weight reduction from a mechanism that has never carried a modern obesity drug by itself.

Amylin receptor agonism in the brainstem reduces meal size and prolongs the interval before hunger returns.

In practice that describes the same subjective experience people report on GLP-1 drugs, arrived at through a different receptor: meals ending sooner, and less interest in the next one.

This was measured in REDEFINE 1, where cagrilintide alone produced about 11.5% mean weight reduction. That is short of semaglutide's roughly 15% and well short of tirzepatide, which is why it is being developed mainly as a partner rather than a standalone.

Larger weight loss in combination#

The claim is that adding cagrilintide to semaglutide produces more than either does alone, because the two act on separate receptors.

Amylin signalling in the brainstem and GLP-1 signalling in the hypothalamus and brainstem are additive rather than overlapping, at least in the trial results so far.

Put another way, the combination does not simply give a bigger dose of the same signal. It sends two.

This was measured in the REDEFINE programme, where CagriSema reached about 22.7% mean weight reduction. That sits between semaglutide alone and tirzepatide, in separate trials rather than a head-to-head.

Better tolerability than raising a GLP-1 dose#

The claim is that reaching a given amount of weight loss with two moderate mechanisms is easier to tolerate than reaching it by pushing one mechanism harder.

Nausea on GLP-1 drugs is dose-related, so splitting the effort across two receptors should in principle allow a lower dose of each.

Whether that matters to you depends on whether nausea was the limiting factor. For a substantial minority of people on these drugs, it is.

This is the least established of the three claims. The mechanism is plausible and the trial data has not isolated it, because CagriSema was not compared against a maximally dosed semaglutide arm designed to answer this question.

What the evidence actually supports#

• Species and route. Human, at the route people would use, in randomised trials. That is a considerably stronger footing than most compounds covered on this site.
• Concentration of sources. Novo Nordisk. Every pivotal trial. There is no independent replication because the drug is not licensed and nobody else has the molecule.
• Human data. The REDEFINE programme has reported topline results. Topline is not full publication, and the detailed papers matter more here than usual, because the interesting question is how the two mechanisms interact rather than what the headline number was.
• What has not been looked at. Cardiovascular outcomes. Long-term use. And the tolerability claim above, which would need a trial designed specifically to test it.

The summary: this is a real drug with real randomised evidence, at an earlier stage than the licensed incretins, and its most likely future is as half of a combination rather than as a product in its own right.

Side effects and safety profile#

The reported profile is the familiar one: nausea, vomiting and reduced appetite, dose-related and worst early. Amylin analogues slow gastric emptying, so the mechanism behind the nausea is much the same as with the GLP-1 drugs even though the receptor differs.

One item belongs in a different category.

That warning comes from a licensed drug in the same class rather than from cagrilintide's own trials, which is exactly why it belongs here. The mechanism is shared, and the failure mode is acute.

How it is dosed and administered#

Cagrilintide has no approved dose, because it has no approval anywhere.

In the trials it was given as a once-weekly subcutaneous injection with a stepped escalation, in the same pattern the incretin drugs use and for the same reason. The CagriSema programme pairs it with semaglutide in a single weekly injection.

Protocols circulating outside clinical settings report copying the trial escalation. It is worth stating what those numbers are: doses lifted from a programme in which participants were screened, monitored, and given a compound whose identity and concentration were guaranteed. None of that travels with the number, and nothing on a vial's label establishes what is in it. Third-party testing and what a COA proves covers the difference.

Cagrilintide compared with the incretin drugs#

Against semaglutide#

Semaglutide reached roughly 15% in STEP; cagrilintide alone reached about 11.5% in REDEFINE 1. On weight alone semaglutide is ahead, and it also has a completed cardiovascular outcomes trial that cagrilintide has no equivalent of.

The more useful comparison is not either-or. CagriSema exists because the two mechanisms are separate, and 22.7% is more than either alone.

Against tirzepatide#

Tirzepatide reached about 20% in SURMOUNT-1 as a single licensed product. CagriSema's 22.7% is a combination of two compounds, in a separate trial, against different participants. Comparing across trials is the least reliable form of comparison, and the head-to-head has not been run.

Against retatrutide#

Retatrutide reported up to 28.3% by adding a third incretin receptor. It is the opposite strategy to cagrilintide's: more of the same family of receptors, rather than a different family entirely.

Frequently asked questions#

What is CagriSema?

Cagrilintide and semaglutide combined in one weekly injection. It reached about 22.7% mean weight reduction in the REDEFINE programme, against roughly 15% for semaglutide alone.

How is amylin different from GLP-1?

Different hormone, different receptors, different site of action in the brain, and released from the pancreas rather than the gut. The subjective effect on appetite is similar, which is why the two combine usefully rather than duplicating each other.

Is it available?

No. It is not approved in any country, alone or in combination, and the trial results describe a compound of verified identity that a vial bought elsewhere does not establish.

Does it cause the same nausea as the GLP-1 drugs?

Nausea is common and dose-related. The receptor is different but the slowed gastric emptying is not, so the experience is broadly similar.

Key takeaways#

• Cagrilintide is a long-acting amylin analogue, not an incretin drug. It acts on brainstem receptors rather than the GLP-1 receptor.
• Alone it produced about 11.5% mean weight reduction in REDEFINE 1. As CagriSema, combined with semaglutide, that reached about 22.7%.
• Its significance is being a second, separate appetite pathway, which is why it is being developed as half of a combination rather than as a standalone product.
• Amylin analogues interact with insulin. The earlier drug in this family carries a severe hypoglycaemia warning when the two are combined.
• It is not approved anywhere, has no cardiovascular outcomes data, and every pivotal trial has one sponsor.

References#

1. Lau DCW et al. Once-weekly cagrilintide for weight management in people with overweight and obesity. The Lancet, 2021.
2. Novo Nordisk. REDEFINE 1 trial results for CagriSema.
3. The compound page on this site: cagrilintide.