Cagrilintide

Cagrilintide (development codes AM833 and NNC0174-0833) is a synthetic, long-acting analogue of amylin, a 37-amino-acid pancreatic hormone that beta cells release into the bloodstream alongside insulin after a meal. It is being developed by Novo Nordisk as an injectable candidate for weight management, both on its own and in a fixed combination with semaglutide known as CagriSema.

Native human amylin is a difficult molecule to turn into a medicine. It aggregates readily into amyloid fibrils, and it clears from circulation within minutes. The medicinal chemistry work published by Kruse and colleagues in the Journal of Medicinal Chemistry in 2021 describes how the Novo Nordisk team stabilized the backbone against fibrillation and added a lipid side chain, arriving at cagrilintide as the candidate selected for clinical development with obesity as the target indication.

Structurally, cagrilintide remains a 37-residue peptide with the intramolecular disulfide bridge characteristic of the amylin and calcitonin family, plus a C20 diacid acyl chain. Its molecular formula is C₁₉₄H₃₁₂N₅₄O₅₉S₂ for a molecular weight of approximately 4,409 g/mol, placing it in the same size class as other acylated metabolic peptides rather than the small repair peptides such as BPC-157.

Functionally, cagrilintide is described as a non-selective agonist at the amylin receptors (AMY1, AMY2 and AMY3, formed by the calcitonin receptor paired with receptor activity-modifying proteins) and at the calcitonin receptor itself. That dual profile is deliberate. It distinguishes cagrilintide from pramlintide, the first-generation amylin analogue approved as an adjunct to insulin therapy, which required three daily injections because of its short half-life.

One point matters before any of the data that follow: cagrilintide is an investigational compound. It has not been approved for human use by the FDA, the EMA or any other regulator, and this article is educational content, not medical advice or a protocol.

Amylin and GLP-1 are both meal-related satiety signals, but they reach the brain through different receptors and different circuits. Understanding that separation is the whole rationale for combining them.

GLP-1 is an incretin released by intestinal L cells. Acting at the GLP-1 receptor, it amplifies glucose-dependent insulin secretion, suppresses glucagon, slows gastric emptying and reduces appetite through receptors in the hypothalamus and brainstem. Our GLP-1 guide covers that pathway in detail, and the semaglutide guide covers the best-characterized analogue of that class.

Amylin is co-secreted with insulin from pancreatic beta cells. Its documented physiological roles are to slow gastric emptying, suppress postprandial glucagon secretion and promote satiation. It signals largely through the area postrema in the brainstem, a circumventricular region outside the blood-brain barrier, and its receptors are built from the calcitonin receptor combined with receptor activity-modifying proteins. Preclinical work has also described amylin as modulating leptin sensitivity, though that mechanism is better supported in animal models than in humans.

The practical consequence is pharmacological complementarity. Two satiety pathways that converge on food intake but engage different receptors can, in principle, be added together without simply saturating one receptor system. That hypothesis is exactly what the phase 1b and phase 2 combination studies were designed to test, and it is the reason a molecule with modest standalone efficacy became interesting as a partner for semaglutide.

It also means the tolerability profiles overlap in a predictable way. Both pathways slow gastric emptying and both act on nausea-related brainstem circuits, which is why gastrointestinal adverse events appear at the top of the safety tables for amylin analogues, GLP-1 analogues and their combination alike.

The engineering problem with amylin has always been duration. Native amylin is cleared within minutes, and pramlintide, the first analogue to reach the market, still needed dosing at every main meal. Cagrilintide was designed around that limitation.

The solution is acylation: attaching a C20 fatty diacid side chain to the peptide. The lipid binds reversibly to circulating albumin, which creates a large, slowly equilibrating reservoir of drug, shields the peptide from renal filtration and from proteolytic degradation, and releases free peptide gradually. This is the same albumin-binding strategy used in several approved metabolic peptides.

In the randomized, placebo-controlled multiple-ascending-dose phase 1b trial reported by Enebo and colleagues in The Lancet in 2021, participants received once-weekly subcutaneous cagrilintide across a dose range of 0.16 mg to 4.5 mg. The reported elimination half-life was on the order of 159 to 195 hours, roughly seven to eight days, with median time to maximum concentration between 24 and 72 hours. A half-life in that range is what allows steady-state exposure to be maintained with a single injection per week.

That same trial was the first to administer cagrilintide together with semaglutide 2.4 mg in humans. Its purpose was safety, tolerability, pharmacokinetics and pharmacodynamics rather than efficacy, and its central finding for the development program was that the pharmacokinetics of the two molecules did not interfere with each other in a way that would block co-formulation.

A long half-life cuts both ways. It smooths exposure and reduces injection burden, but it also means that if an adverse effect appears, the compound is not cleared quickly. In a clinical trial that is managed by protocol-driven dose adjustment and medical supervision, neither of which exists outside a trial setting.

The reference dataset for cagrilintide as a single agent is the phase 2 dose-finding trial published by Lau and colleagues in The Lancet in 2021. It was a multicentre, randomized, double-blind, placebo-controlled and active-controlled study run at 57 sites in ten countries, enrolling 706 adults with obesity, or overweight with at least one weight-related comorbidity, and without type 2 diabetes.

Participants were randomized to once-weekly subcutaneous cagrilintide at 0.3, 0.6, 1.2, 2.4 or 4.5 mg, to once-daily liraglutide 3.0 mg as an active comparator, or to placebo, all on top of a lifestyle intervention, for 26 weeks. The design deliberately included an approved anti-obesity agent as a benchmark rather than testing against placebo alone.

At 26 weeks, the highest cagrilintide dose produced a mean body-weight reduction of 10.8 percent, compared with 3.0 percent for placebo and 9.0 percent for liraglutide 3.0 mg. A dose-response relationship was visible across the cagrilintide arms. The authors concluded that cagrilintide led to significant reductions in body weight and was well tolerated in this population.

Two caveats belong next to those numbers. First, 26 weeks is a short horizon for an obesity intervention, well below the 68-week standard now used in registrational obesity trials, so the curve had not plateaued. Second, the comparison with liraglutide is informative but does not extend to the more potent agents that define the current standard of care. Cagrilintide alone reached a level of efficacy that was interesting but not clearly differentiating, which is a large part of why the program pivoted toward combination.

Later phase 3 work gave a longer look at monotherapy. In REDEFINE 1, the cagrilintide 2.4 mg arm produced an estimated mean weight change of -11.5 percent at 68 weeks, consistent in magnitude with the phase 2 signal.

CagriSema is the fixed-dose combination of cagrilintide 2.4 mg and semaglutide 2.4 mg in a single once-weekly subcutaneous injection. It is the form in which cagrilintide has been carried into phase 3 and submitted for regulatory review.

The first efficacy signal came from the phase 2 trial reported by Frias and colleagues in The Lancet in 2023, conducted at 17 sites in the USA in 92 adults with type 2 diabetes. Over 32 weeks, mean weight loss was 15.6 percent with the combination, versus 8.1 percent with cagrilintide alone and 5.1 percent with semaglutide alone. HbA1c fell by 2.2 percentage points with the combination, versus 1.8 with semaglutide and 0.9 with cagrilintide. The combination beat cagrilintide on HbA1c but was not significantly different from semaglutide on that endpoint.

The pivotal result is REDEFINE 1, published in the New England Journal of Medicine in 2025 by Garvey and colleagues for the REDEFINE 1 Study Group. A total of 3,417 adults with overweight or obesity and without diabetes were randomized, with 2,108 to cagrilintide-semaglutide, 302 to semaglutide, 302 to cagrilintide and 705 to placebo, and treated for 68 weeks. The estimated mean percent change in body weight was -20.4 percent with the combination versus -3.0 percent with placebo, with semaglutide alone at -14.9 percent and cagrilintide alone at -11.5 percent. Novo Nordisk reported a mean reduction of 22.7 percent under the estimand that models full adherence to treatment.

REDEFINE 2, published simultaneously by Davies and colleagues, tested the combination in 1,206 adults with type 2 diabetes and overweight or obesity over 68 weeks. Mean body-weight change was -13.7 percent with cagrilintide-semaglutide versus -3.4 percent with placebo, a difference of 10.4 percentage points, and 73.5 percent of the combination group reached an HbA1c of 6.5 percent or lower versus 15.9 percent on placebo. As is consistently observed in obesity pharmacology, weight loss is attenuated in the type 2 diabetes population relative to people without diabetes.

Read together, these trials support the additive-pathway hypothesis: adding amylin agonism to GLP-1 agonism produced more weight loss than either component alone within the same trial. What they do not establish is superiority over the broader class, which is a separate question addressed below.

This section is a factual positioning exercise, not a recommendation. Cross-trial comparisons are weak evidence because populations, durations, estimands and background lifestyle interventions differ. Within-trial comparisons are the only reliable kind, so they are flagged as such below.

Within REDEFINE 1, which is a direct randomized comparison, the combination (-20.4 percent) outperformed semaglutide 2.4 mg alone (-14.9 percent) and cagrilintide 2.4 mg alone (-11.5 percent) at 68 weeks. That is the strongest internal evidence that the amylin component adds something on top of GLP-1 agonism.

Against tirzepatide, the picture is different. Novo Nordisk released headline results from the REDEFINE 4 head-to-head trial in February 2026: 809 adults with obesity and at least one comorbidity, randomized to CagriSema 2.4/2.4 mg or tirzepatide 15 mg once weekly for 84 weeks. The company reported weight reductions of 23.0 percent with CagriSema versus 25.5 percent with tirzepatide under the efficacy estimand, and 20.2 percent versus 23.6 percent under the treatment-regimen estimand. CagriSema did not meet its primary endpoint of non-inferiority to tirzepatide 15 mg. These are company-announced headline data, and as of this writing a full peer-reviewed report has not appeared, so the detail on subgroups, discontinuations and safety remains to be published.

The mechanistic comparison is worth stating plainly. Semaglutide is a single-pathway GLP-1 receptor agonist. Tirzepatide is a dual GIP and GLP-1 receptor agonist, and our semaglutide versus tirzepatide comparison reviews the head-to-head evidence between those two. CagriSema pairs GLP-1 agonism with amylin agonism. Further out, retatrutide adds glucagon receptor agonism as a third arm. Each combination is a different bet about which satiety and energy-expenditure pathways stack usefully.

None of this translates into a ranking for any individual. Efficacy averages in trials say nothing about tolerability, comorbidities, contraindications, drug interactions, access or cost for a given person. Those are clinical decisions that belong with a qualified healthcare professional working from an individual medical history.

Across every cagrilintide dataset published so far, gastrointestinal adverse events lead the safety tables. This is expected from the mechanism: both amylin and GLP-1 signaling slow gastric emptying and engage brainstem nausea circuits.

In REDEFINE 1, gastrointestinal adverse events were reported in 79.6 percent of participants receiving cagrilintide-semaglutide versus 39.9 percent receiving placebo. The reported events were nausea, vomiting, diarrhea, constipation and abdominal pain, described by the investigators as mainly transient and mild to moderate in severity. The gap between the active and placebo arms is large, but the high placebo rate is a reminder that background gastrointestinal symptoms are common in this population and that uncontrolled reports overstate attribution.

In the phase 2 monotherapy trial, cagrilintide was described as well tolerated across the dose range tested, with gastrointestinal events again the most frequent category and a dose relationship in their frequency. Dose escalation schedules in all of these trials were designed specifically to mitigate early nausea, which is why headline tolerability from a slow-titration protocol cannot be assumed to apply to any other pattern of use.

Beyond gastrointestinal effects, the classes involved carry considerations that are documented for approved GLP-1 receptor agonists and that phase 3 programs monitor: injection-site reactions, gallbladder-related events associated with rapid weight loss, heart rate changes, and the loss of lean mass that accompanies large reductions in total body weight. Long-term safety for the amylin component specifically, over horizons of several years, has not yet been characterized.

Medical disclaimer: this content is for educational purposes only. Cagrilintide is not approved for human use. It is not a treatment, and nothing here should be read as a protocol. Anyone considering pharmacological weight management should consult a healthcare professional, who can assess contraindications, interactions and personal risk. Legal status of investigational peptides varies by jurisdiction.

As of September 2026, cagrilintide is not approved by any regulatory agency, neither on its own nor as part of CagriSema. It remains an investigational medicinal product in clinical development.

Novo Nordisk submitted a New Drug Application to the US FDA for CagriSema for weight management in December 2025, based principally on the REDEFINE 1 and REDEFINE 2 phase 3 results. Company guidance has pointed to a regulatory decision in the latter part of 2026. A filing is not an approval, and a review can end in approval, a request for more information, or rejection.

The clinical program has continued to expand in parallel. Beyond the REDEFINE obesity trials, the REIMAGINE studies have examined cagrilintide-semaglutide in type 2 diabetes, including as an add-on to basal insulin, with reports appearing in The Lancet family of journals during 2026. Each additional indication carries its own regulatory pathway and its own timeline.

A separate point deserves emphasis because it is widely misrepresented online. There is no validated research-grade or consumer form of cagrilintide. Material sold outside of the clinical supply chain is not the trial product, has not been characterized for identity, purity, aggregation state or sterility by any regulator, and cannot be assumed to behave like the compound described in the publications above. Amylin analogues are particularly sensitive on this point given the fibrillation tendency the medicinal chemistry work was specifically designed to overcome.

Klow Peptide does not list cagrilintide in its catalogue and does not link to any supplier for it. That is a deliberate editorial position, not an oversight, and it reflects the fact that the compound exists at present only inside a regulated clinical program.

The published record is unusually strong for a compound at this stage, with two large phase 3 trials in a top-tier journal. It is still incomplete in several specific ways.

Cardiovascular outcomes. Weight reduction is a surrogate endpoint. Whether cagrilintide-semaglutide reduces major adverse cardiovascular events, as has been demonstrated for some GLP-1 receptor agonists in dedicated outcome trials, has not been established. Weight loss trials are not powered for that question.

The isolated contribution of amylin over the long run. REDEFINE 1 quantified cagrilintide alone at 68 weeks, but the development path is the combination. How much of the added benefit comes from amylin agonism specifically, in which patients, and whether it persists beyond two years are open questions. The REDEFINE 4 result against tirzepatide also raises the question of whether amylin agonism adds as much on top of GLP-1 as GIP agonism does, which no trial has yet tested directly.

Durability and discontinuation. As with the rest of the class, what happens to body weight after stopping treatment is a central practical question, and the published follow-up is limited. Long-term safety of chronic calcitonin receptor engagement, including effects on bone and calcium handling, has not been characterized over multi-year horizons.

Special populations. Data in older adults, in people with significant renal or hepatic impairment, in adolescents and during pregnancy are absent or minimal, as is standard at this stage of development. Interactions with the full range of concomitant medications are similarly incomplete.

Honest reading of this evidence base means holding two things at once: the phase 3 efficacy signal is substantial and well documented, and the compound is still investigational with meaningful unanswered questions. Both statements are true.

This section deliberately contains no units, no quantities and no schedule. It is about record-keeping methodology, which is a legitimate and separable topic from what anyone should put in a syringe.

Any injectable peptide supplied as a lyophilized powder raises the same arithmetic questions once reconstituted: how much total compound the container held, what volume of diluent was added, what concentration results, how many administrations a container covers, and when it was opened. Getting that arithmetic wrong is one of the most common and most consequential errors in this space, because an error of a factor of ten is easy to make and impossible to see in a clear solution.

Three things are worth documenting systematically in a research or clinical-record context: concentration after reconstitution, date of reconstitution (peptides in solution have a finite stability window under refrigeration), and a running balance of what remains in the container. A written or digital log removes reliance on memory and makes any inconsistency visible early.

• Record the lot and the reconstitution date at the moment the container is opened, not later.
• Keep the concentration calculation written down rather than recomputed each time.
• Track the remaining balance after every withdrawal so the container's end point is never a surprise.
• Note storage conditions and any temperature excursion.

The Peptide Lab cagrilintide calculator handles this arithmetic and the running balance. It is a calculation and tracking utility: it does not recommend a quantity, a frequency or a schedule, and it is not a substitute for professional medical supervision. For an investigational compound such as cagrilintide, the only appropriate context for administration is a supervised clinical trial.