At a glance: Cagrilintide is a once-weekly injectable version of the hormone amylin, developed by Novo Nordisk for weight management. It has been through large human trials, mostly as CagriSema (cagrilintide plus semaglutide). It is not FDA-approved yet: Novo filed CagriSema with the FDA in December 2025 and expects a decision in late 2026.
What is cagrilintide?
Cagrilintide is a lab-made, long-acting analog of amylin, a 37-amino-acid hormone released by the pancreas together with insulin after meals. Natural amylin lasts only minutes in the body; cagrilintide has been modified to last about a week, allowing once-weekly injections.
It is not a GLP-1 drug like semaglutide (Wegovy) or tirzepatide (Zepbound). It acts on a different hormone system, amylin receptors, which is why Novo Nordisk is developing it mainly in combination with semaglutide.
How does cagrilintide work?
- Increases fullness: acts on appetite centers in the brainstem and hypothalamus, so people feel satisfied sooner and eat less
- Slows stomach emptying, which prolongs fullness after meals and softens blood sugar spikes
- Lowers glucagon after meals, a hormone that raises blood sugar
- Uses a different pathway than GLP-1 drugs, so combining the two can add to the effect rather than duplicate it
What the research shows
Cagrilintide is one of the few compounds on this site with large, modern, placebo-controlled human trials.
| Trial | Who was studied | Main finding |
|---|---|---|
| Phase 2, cagrilintide alone (Lau et al., Lancet 2021) | 706 adults with overweight or obesity, 26 weeks | Up to 10.8% weight loss at the highest dose vs 3.0% on placebo |
| Phase 2, CagriSema (Frias et al., Lancet 2023) | Adults with type 2 diabetes and overweight, 32 weeks | About 15.6% weight loss, more than either drug alone |
| REDEFINE 1 (NEJM 2025) | About 3,400 adults with obesity, no diabetes, 68 weeks | CagriSema 20.4% weight loss (22.7% in those who stayed on treatment); cagrilintide alone 11.5%; semaglutide alone 14.9%; placebo 3.0%. About 40% on CagriSema lost at least 25% of body weight |
| REDEFINE 2 (NEJM 2025) | About 1,200 adults with obesity and type 2 diabetes, 68 weeks | CagriSema 13.7% weight loss vs 3.4% on placebo, with improved blood sugar |
| REDEFINE 4 (announced 2026) | CagriSema vs tirzepatide, 84 weeks | About 23% weight loss on CagriSema, but it did not meet its main goal of proving it was at least as good as tirzepatide |
REDEFINE 3, a long-term trial of heart outcomes, is ongoing.
Why it gets attention
- A new hormone target beyond GLP-1, the class behind today's best-selling weight-loss drugs
- Big combined results: CagriSema produced some of the largest average weight losses seen in a phase 3 trial
- Possible better-quality weight loss: early data suggest relatively more fat than muscle is lost, though this needs confirmation
- Gray-market demand: cagrilintide is sold online as a "research peptide" ahead of any approval
How it is given
In trials, cagrilintide and CagriSema were given as a once-weekly injection under the skin, with the dose increased gradually over several months to limit stomach side effects. CagriSema combines both drugs in a single weekly injection. Because it is not approved, there is no official label, and this page does not provide dosing guidance.
What about side effects?
In the trials, side effects were similar to those of GLP-1 drugs:
- Common: nausea, vomiting, diarrhea and constipation, mostly mild to moderate and most frequent while the dose is being increased
- Expected: reduced appetite, which is how the drug works
- Less common: injection-site reactions
- Expected precautions (based on the semaglutide component and drug class): not for people with a personal or family history of medullary thyroid cancer or MEN 2, and not for use in pregnancy. Final warnings will be set by regulators if approved.
Long-term safety beyond the trial periods is still being studied. Products sold online as "research cagrilintide" are not the trial drug and have no quality guarantees.
Regulatory status
- Not approved by the FDA, EMA or UK regulators as of this update.
- Novo Nordisk submitted a New Drug Application for CagriSema to the FDA on December 18, 2025, based on REDEFINE 1. The company has guided to a US decision in the fourth quarter of 2026.
- Cagrilintide alone has not been submitted for approval; it appears in trials mainly as a comparison arm.
- Cagrilintide sold online as a "research peptide" is unregulated and not intended for human use.
How it compares to other weight-loss medicines
| Cagrilintide | CagriSema | Semaglutide (Wegovy) | Tirzepatide (Zepbound) | |
|---|---|---|---|---|
| Hormone target | Amylin | Amylin + GLP-1 | GLP-1 | GIP + GLP-1 |
| Average weight loss in key trial | About 11.5% (68 weeks) | About 20.4% (68 weeks) | About 14.9% (68 weeks) | About 20.9% (72 weeks) |
| US status | Not approved; not filed alone | Under FDA review | FDA-approved | FDA-approved |
Trial results are not directly comparable across different studies and populations.
The bottom line
Cagrilintide is a serious, well-studied drug candidate rather than a fringe research peptide. Large trials show meaningful weight loss on its own and substantial weight loss combined with semaglutide. But it is not approved yet, its long-term heart outcomes are still being studied, and versions sold online are not the trial product. Anyone interested should talk with a clinician about approved options while the FDA review is pending.
Frequently asked questions
What is Cagrilintide?
A long-acting version of amylin, a hormone released alongside insulin that affects fullness. It is being developed together with semaglutide as a combination called CagriSema.
How is Cagrilintide taken?
Weekly subcutaneous injection (trials).
Is Cagrilintide FDA approved?
Not approved; CagriSema was submitted to the FDA in December 2025.
That means no regulator has reviewed its safety, effectiveness or manufacturing quality for this use.
What has research shown about Cagrilintide?
- Weight loss on its own and combined with semaglutide in clinical trials.
- In the phase 3 REDEFINE 1 trial, the CagriSema combination led to a mean weight loss of 22.7% at 68 weeks.
What side effects have been reported?
- Nausea
- Vomiting
- Diarrhoea
- Constipation
Serious or less common risks are listed in the Side Effects section above.
What is still unknown about its safety?
Most of it. Cagrilintide has not been through the trials that establish long-term safety in people, and products sold online are made by unregulated labs. Independent testing of online peptides has repeatedly found contents that do not match the label.
References
- Lau DCW, et al. Once-weekly cagrilintide for weight management in people with overweight and obesity: a multicentre, randomised, double-blind, placebo-controlled and active-controlled, dose-finding phase 2 trial. Lancet. 2021. View source
- American Diabetes Association: CagriSema demonstrates significant weight loss in adults with obesity (REDEFINE 1 and 2, NEJM, June 2025). View source
- Drugs.com: CagriSema approval history and timeline (NDA submission, REDEFINE 4). View source
- MyPeptideStory: CagriSema PDUFA date and FDA approval status (2026). View source
- The Care Pharmacy: Cagrilintide, what it is and how it works (2026). View source