What Is Cagrilintide?

Cagrilintide is a synthetic peptide analogue of amylin, a 37-amino-acid hormone co-secreted with insulin by the beta cells of the pancreas. Natural amylin has a very short half-life in circulation, which limits its therapeutic usefulness. Cagrilintide was engineered by Novo Nordisk to extend that half-life dramatically, allowing once-weekly subcutaneous administration in clinical trials rather than the multiple daily injections required by pramlintide, the only approved amylin analogue on the U.S. market.

The structural modifications include fatty-acid acylation, a technique also used in semaglutide and insulin degludec to promote albumin binding and slow renal clearance. The result is a molecule that retains amylin-like receptor activity but circulates long enough to be studied with weekly administration in trials. Cagrilintide is sometimes referred to by its development code AM833 in earlier literature.

As of mid-2025, cagrilintide itself has no standalone FDA approval or equivalent regulatory clearance in any major market. It is a research compound being evaluated in registered clinical trials. The combination product pairing cagrilintide with semaglutide, referred to as CagriSema, is the primary vehicle through which Novo Nordisk is advancing the compound toward potential approval.

How Does Cagrilintide Work?

Amylin receptors are found in several brain regions involved in energy balance, particularly the area postrema and the nucleus of the solitary tract in the brainstem. When amylin or an analogue binds these receptors, it signals satiety, slows the rate at which the stomach empties food into the small intestine, and suppresses glucagon secretion after meals. Cagrilintide is understood to act through the same receptor system, producing these effects with a longer duration because of its modified structure.

Researchers are also interested in what happens when amylin-pathway signalling is combined with GLP-1 receptor agonism. GLP-1 receptors and amylin receptors are expressed in overlapping but distinct brain circuits. The hypothesis driving the CagriSema program is that activating both pathways simultaneously produces greater appetite suppression and weight loss than either mechanism alone. This is a pharmacological rationale, not a proven outcome, and the clinical trials are designed to test whether the hypothesis holds in humans.

It is worth being precise about the evidence base here. The mechanistic picture described above draws on receptor pharmacology studies and animal data. Human trials measure outcomes like body weight and blood glucose, but the exact sequence of neurological events producing those outcomes in people is inferred rather than directly observed. Mechanism descriptions in peptide research often run ahead of what human studies have confirmed.

What Does the Human Clinical Evidence Show?

The most cited early human data come from a phase 2 randomized controlled trial published in The Lancet in 2021. That trial enrolled 706 adults with overweight or obesity and tested multiple doses of cagrilintide as a monotherapy against placebo over 26 weeks. Participants receiving the highest tested amount (4.5 mg weekly) lost a mean of approximately 10.8% of body weight compared with 3.0% in the placebo group. The trial also reported dose-dependent reductions in HbA1c among participants who had elevated baseline levels. Adverse events were predominantly gastrointestinal, consistent with the amylin mechanism, and included nausea and vomiting.

The combination program has generated its own phase 2 data. A trial published in The Lancet in 2023 examined CagriSema (cagrilintide 2.4 mg plus semaglutide 2.4 mg, administered weekly in the trial) in adults with overweight or obesity over 32 weeks. Participants in the combination arm lost a mean of 15.6% of body weight, compared with 5.1% for cagrilintide alone and 5.1% for semaglutide alone at the amounts tested in that trial. The sample size was modest at 92 participants across all arms, which limits the conclusions that can be drawn.

Phase 3 trials are ongoing. The REDEFINE program is a set of large, long-duration trials evaluating CagriSema in people with obesity and in people with type 2 diabetes. These trials are registered on ClinicalTrials.gov and are designed to generate the safety and efficacy data that would support a regulatory submission. Results from the first REDEFINE trial reported in early 2025 showed approximately 22.7% mean weight loss in the CagriSema arm over 68 weeks, though full peer-reviewed publication of those data was pending at the time of writing.

Animal and Preclinical Evidence

Before human trials began, cagrilintide was studied in rodent and non-human primate models. Diet-induced obese mouse and rat studies showed reductions in food intake, body weight, and fasting glucose following cagrilintide administration. These findings provided the biological rationale for advancing the compound into human trials, but animal results do not reliably predict human outcomes, and this distinction matters when evaluating any peptide research program.

Preclinical work also examined the combination of amylin analogues with GLP-1 receptor agonists in animal models before CagriSema entered human trials. Studies in obese rodents suggested additive or synergistic effects on body weight when both pathways were activated together. Again, these are animal findings. They informed the design of human trials but cannot substitute for human data.

In-vitro receptor binding studies have characterized how cagrilintide interacts with amylin receptor subtypes, including the calcitonin receptor complexed with receptor activity-modifying proteins. This work helps researchers understand selectivity and potency at the molecular level, but in-vitro binding data sit at the bottom of the evidence hierarchy and say nothing directly about clinical outcomes.

What Are the Honest Limits of the Evidence?

The human evidence for cagrilintide is more developed than for most research peptides covered on this site, because it has progressed through phase 2 and into phase 3 trials with a large pharmaceutical sponsor. That said, several important gaps remain. The phase 2 monotherapy trial ran for only 26 weeks, which is not long enough to assess long-term safety or whether weight loss is maintained. Long-term cardiovascular outcome data, which regulators typically require for obesity drugs, are not yet available for cagrilintide or CagriSema.

The most striking weight-loss figures in the literature come from the CagriSema combination, not from cagrilintide alone. Separating the contribution of each component is methodologically difficult, and the 2023 phase 2 trial was not powered to make definitive comparisons between arms. The phase 3 REDEFINE trials will provide cleaner data, but full results and peer-reviewed publication were not complete as of mid-2025.

Cagrilintide is not available as an approved medicine. Branded pharmaceutical forms of semaglutide (Ozempic and Wegovy, approved by the FDA) are separate products and are not the same as research-grade semaglutide or cagrilintide sold by peptide vendors. Anyone encountering cagrilintide outside of a clinical trial setting is dealing with a compound that has no regulatory approval, no verified manufacturing standards enforced by a regulator, and no established safety profile in that context.

Frequently asked questions

Is cagrilintide the same thing as CagriSema?

No. Cagrilintide is a single compound, an amylin analogue. CagriSema is the name Novo Nordisk uses for the fixed combination of cagrilintide and semaglutide being studied together in clinical trials. The two names are sometimes used interchangeably in media coverage, but they refer to different things.

How does cagrilintide differ from pramlintide, the approved amylin analogue?

Pramlintide (brand name Symlin) is an amylin analogue approved by the FDA for use alongside insulin in adults with type 1 or type 2 diabetes. It has a short half-life and requires multiple daily injections. Cagrilintide uses fatty-acid acylation to extend its half-life, allowing once-weekly administration in clinical trials. The two compounds also differ in their development context: pramlintide is an approved prescription drug, while cagrilintide has no regulatory approval.

What side effects appeared in cagrilintide clinical trials?

In the 2021 phase 2 trial published in The Lancet, the most commonly reported adverse events were gastrointestinal, including nausea, vomiting, and decreased appetite. These are consistent with the known effects of amylin receptor activation and are similar to side effects seen with GLP-1 receptor agonists. Adverse event rates were generally higher at higher tested amounts and tended to decrease over time in the trial. This is trial-reported data and does not capture what might occur outside a controlled research setting.

Sources

  1. Enebo et al., 2021, The Lancet Phase 2 RCT of cagrilintide monotherapy in obesity
  2. Lau et al., 2023, The Lancet Phase 2 trial of CagriSema combination in obesity
  3. ClinicalTrials.gov, REDEFINE 1, NCT05567796 Phase 3 CagriSema trial registration

Educational and informational content only. This is not medical advice, diagnosis, or treatment. The compounds discussed are research compounds that are not approved for human use outside specific prescribed contexts. Always consult a qualified, licensed clinician before making any health decision.