Cagrilintide: The Complete Guide to the Long-Acting Amylin Analog (2026)

Cagrilintide is a long-acting, lab-engineered version of amylin, a natural "I'm full" hormone your pancreas releases alongside insulin after a meal. It is designed to be injected just once a week, and it is being developed mainly as a weight-loss treatment, one of several peptides used for weight loss, most famously paired with semaglutide in a combination called CagriSema. The headline caveat is that cagrilintide is investigational: it is not approved by any regulator, and almost everything known about it comes from clinical trials, not real-world prescribing.

If you have heard cagrilintide called "the amylin half of CagriSema," seen the 22.7% weight-loss number in the news, or run across it sold as a research peptide, this guide is the high-level map of the whole compound. We cover what it actually is, how its mechanism works, what it is studied for, the doses used in trials, side effects, realistic results, the honest safety picture, and its investigational legal status. Each section is a clear overview; the deep-dive topics (a full dosing chart, side-effect management, the head-to-head versus semaglutide, the CagriSema breakdown) point to dedicated guides so this page stays a clean hub.

Key Takeaways

• Cagrilintide (research code AM833) is a long-acting synthetic analog of the hormone amylin, modified with a fatty-acid side chain so a single subcutaneous injection lasts about a week (The Lancet, 2021, retrieved 2026-06-15).
• It is not FDA-approved. Cagrilintide is investigational and in Phase 3 trials. Novo Nordisk filed a U.S. FDA application for CagriSema (cagrilintide + semaglutide) for weight management on December 18, 2025, with a decision expected in 2026 (Novo Nordisk / PR Newswire, 2025).
• It works through amylin, not GLP-1. Cagrilintide activates amylin receptors (AMY1R and AMY3R) in the hindbrain to increase satiety, reduce appetite, and slow gastric emptying (eBioMedicine, 2025).
• In trials it produces meaningful weight loss. Cagrilintide 2.4 mg alone gave about 11.5% mean weight loss over 68 weeks; combined with semaglutide as CagriSema it reached 22.7% in the REDEFINE 1 trial (NEJM, 2025).
• Doses studied climb from 0.25 mg to 2.4 mg weekly (up to 4.5 mg in early dose-finding), reached by a slow several-week titration to limit nausea. These are trial figures, not a validated consumer dose. The full ladder is a future dosing chart spoke.
• The main side effects are gastrointestinal (nausea, constipation, vomiting), mostly mild-to-moderate and worst during dose escalation (The Lancet, 2021).

What is cagrilintide?

Cagrilintide is a long-acting, synthetic analog of amylin, a natural fullness hormone, engineered to be injected once a week for weight management. Its research name is AM833, and it is developed by Novo Nordisk. It is studied almost entirely for obesity and, in combination, for type 2 diabetes.

Amylin is a 37-amino-acid hormone your pancreas secretes together with insulin after eating; it signals fullness and helps control how fast food leaves the stomach. Natural amylin is sticky and short-lived, which makes it hard to use as a drug. Cagrilintide is a re-engineered version with a fatty-acid side chain (acylation) that lets it bind to blood albumin and stay active far longer, extending its half-life to roughly a week so it can be dosed once weekly by subcutaneous injection (The Lancet, 2021, retrieved 2026-06-15). If injectable peptides are new to you, start with our what are peptides and how peptides work guides.

The single most important fact about cagrilintide is its status: it is not approved by the FDA or any other regulator for any use. It exists in a large, well-run clinical-trial program and, separately, in an unapproved "research chemical" market. Everything else in this guide should be read through that lens.

Citation capsule. Cagrilintide (research code AM833) is a long-acting, acylated synthetic analog of the human hormone amylin, developed by Novo Nordisk. A fatty-acid side chain extends its half-life to about one week, enabling once-weekly subcutaneous dosing. It activates amylin receptors (AMY1R, AMY3R) in the hindbrain to reduce appetite. It is investigational, not approved by any regulator, and is studied for obesity, most prominently combined with semaglutide as CagriSema. Source: The Lancet, 2021; eBioMedicine, 2025; Novo Nordisk, 2025.

How does cagrilintide work?

Cagrilintide works by imitating amylin: it activates amylin receptors in the brainstem that tell your body you are full, which reduces appetite and slows how quickly the stomach empties. Because it uses the amylin pathway rather than the GLP-1 pathway that drugs like semaglutide use, the two can be combined for an additive effect.

In plain terms, cagrilintide turns up the volume on a fullness signal your body already makes. After you eat, amylin normally helps you feel satisfied and slows digestion; cagrilintide does the same thing, longer and stronger. A 2025 mechanistic study in mice pinned down exactly which receptors carry that effect: it reduces body weight "through amylin receptors 1 and 3 (AMY1R and AMY3R)," which are calcitonin-receptor complexes acting in hindbrain regions including the area postrema and nucleus of the solitary tract, and concluded that cagrilintide depends on those receptors to lower body weight (eBioMedicine, "Cagrilintide lowers bodyweight through brain amylin receptors 1 and 3", 2025, retrieved 2026-06-15).

Here is what each proposed action contributes, in simple terms:

• Amylin-receptor activation (AMY1R / AMY3R): switches on the brain's satiety machinery in the hindbrain, so you feel full sooner and eat less.
• Slowed gastric emptying: food leaves the stomach more slowly, prolonging fullness after a meal.
• Reduced food cravings: by acting on appetite centers, it lowers the drive to eat between meals.
• Complementary to GLP-1: because amylin and GLP-1 are separate pathways, cagrilintide stacks with semaglutide for a larger combined effect (the basis of CagriSema).

The receptor-and-signaling deep dive (how amylin and calcitonin receptors differ, why the hindbrain matters) is its own topic. We keep it at overview level here and link out to how peptides work for the foundations.

What is cagrilintide used for?

Cagrilintide is studied mainly for weight loss in adults with overweight or obesity, and, combined with semaglutide, for type 2 diabetes; none of these are FDA-approved uses yet. Its development is built around the idea that adding an amylin analog to a GLP-1 drug produces more weight loss than either alone.

The headline use is obesity. As a standalone weekly injection it produced clinically meaningful weight loss in trials, but its biggest role is as half of CagriSema, the fixed combination with semaglutide that drove the much-discussed 20%-plus results. Its second angle is metabolic and glycemic control: the REIMAGINE program is testing CagriSema in people with type 2 diabetes, where amylin's effects on appetite and gastric emptying complement GLP-1's blood-sugar benefits (Novo Nordisk / PR Newswire, 2025, retrieved 2026-06-15).

A quick overview of the areas cagrilintide is studied for, and where the evidence stands:

Because each of these is a distinct future spoke, we keep them brief here. The honest headline: cagrilintide's strongest, best-documented use is weight loss, especially as part of CagriSema, and that program is now in front of the FDA.

How does cagrilintide compare to semaglutide and CagriSema?

Cagrilintide and semaglutide are different drugs that hit different pathways, and CagriSema is the fixed combination of the two; together they produce more weight loss than either alone. Cagrilintide is an amylin analog; semaglutide is a GLP-1 receptor agonist.

In rough terms, semaglutide works on the GLP-1 system (the basis of Ozempic and Wegovy), while cagrilintide works on the separate amylin system. Because the pathways are independent, stacking them is additive rather than redundant, which is the whole rationale for CagriSema. In the Phase 3 REDEFINE 1 trial, cagrilintide 2.4 mg alone gave about 11.5% mean weight loss and semaglutide 2.4 mg alone about 14.9%, while the CagriSema combination reached 22.7% (trial-product estimand) over 68 weeks (NEJM via Novo Nordisk / PR Newswire, 2025, retrieved 2026-06-15).

The full head-to-head, including how CagriSema is dosed, how it stacks up against tirzepatide, and the nuance that REDEFINE 1 narrowly missed its own 25% stretch target, is its own spoke. We keep it short here to avoid overlapping that future article: see cagrilintide vs semaglutide and the CagriSema breakdown, and the foundational semaglutide complete guide.

What doses of cagrilintide were studied in trials?

There is no approved or validated consumer dose for cagrilintide, but in trials it was titrated slowly from 0.25 mg up to a 2.4 mg weekly maintenance dose (with up to 4.5 mg explored in early dose-finding). These are the doses studied in clinical research, not a recommendation, and there is no approved label to anchor them.

In the Phase 3 program, cagrilintide is escalated step by step to let the body adjust and limit nausea, with a common ladder of 0.25 mg, then 0.5, 1.0, 1.7, and finally 2.4 mg once weekly, increasing roughly every four weeks (The Lancet, 2021, retrieved 2026-06-15). The earlier Phase 2 dose-finding trial tested seven weekly doses from 0.3 mg to 4.5 mg in 706 adults, and found a clear dose-response, with the top 4.5 mg dose giving the most weight loss (The Lancet, "Once-weekly cagrilintide for weight management", 2021, retrieved 2026-06-15). We label all consumer use as off-label and unstudied because no regulator has reviewed a dose for individuals.

The detailed titration ladder, dose-conversion math, reconstitution volumes, and how CagriSema's fixed-dose pen differs are a dedicated spoke. We cover only the high-level framing here and link out to the our peptide dosing calculator, the our peptide reconstitution calculator, and the general peptide injections guide.

For orientation only, here is the escalation studied in trials (not a recommendation):

Our take: Numbers like "2.4 mg weekly" get repeated so often they start to sound like a settled dose. They are trial doses, reached under medical supervision with a deliberate slow ramp. They are not a validated consumer protocol, which is exactly why we never present them as a recommended dose.

What results can you expect from cagrilintide?

In trials, cagrilintide produced roughly 10-12% mean weight loss on its own and over 20% when combined with semaglutide, built gradually over many months, not weeks. Results are real and clinically meaningful, but they come from supervised trials with slow titration and lifestyle support, so individual outcomes vary widely.

The clearest data come from REDEFINE 1, the Phase 3 trial of 3,417 adults with overweight or obesity (without diabetes), published in the New England Journal of Medicine in June 2025. CagriSema produced a 22.7% mean weight reduction at 68 weeks (trial-product estimand), versus about 2.3% on placebo, and 40.4% of participants on the combination lost at least 25% of their body weight (NEJM via Novo Nordisk / PR Newswire, 2025, retrieved 2026-06-15). For cagrilintide on its own, the earlier Phase 2 trial found a dose-dependent effect, with the 4.5 mg dose reaching about 10.8% mean weight loss at 26 weeks versus 3.0% on placebo and 9.0% on the comparator liraglutide (The Lancet, 2021, retrieved 2026-06-15).

A grounded view of what the trials actually show:

• Standalone weight loss lands around 10-12% on average at the higher doses, comparable to first-generation GLP-1 weight-loss drugs.
• Combination (CagriSema) roughly doubles that, into the 20%-plus range, which is why the combination, not the standalone, is the lead program.
• The curve is slow. These figures are at 26-68 weeks; weight comes off gradually as the dose is escalated, not in the first month.
• One honest caveat: REDEFINE 1's 22.7% narrowly missed Novo Nordisk's own 25% stretch target, a reminder that headline numbers should be read against the trial's pre-set goals.

For grounded before-and-after context and how to read transformation claims, see peptides before and after.

What are the side effects of cagrilintide?

The main side effects of cagrilintide are gastrointestinal, especially nausea, constipation, and vomiting, and they are mostly mild-to-moderate and worst during dose escalation. This profile is typical of appetite-suppressing metabolic drugs and is the reason doses are ramped up slowly.

In the Phase 2 dose-finding trial, gastrointestinal events were the most common adverse effects and were generally mild to moderate, with nausea the leading complaint and a higher rate at higher doses (The Lancet, 2021, retrieved 2026-06-15). Reported community and secondary summaries of the higher 4.5 mg dose put nausea around 47%, injection-site reactions around 43%, constipation around 21%, and vomiting around 8%, with most events resolving as the body adjusted (Peptides.org, 2024, retrieved 2026-06-15). One trial-specific finding to note: a substantial share of participants developed anti-cagrilintide antibodies over the study, but no serious allergic reactions were attributed to them (Peptides.org, 2024, retrieved 2026-06-15).

A hub-level overview of what is reported:

• Common (usually mild-to-moderate): nausea, constipation, vomiting, reduced appetite, fatigue, and injection-site reactions.
• Escalation-related: side effects cluster around dose increases and tend to ease as the body adapts, which is why titration is slow.
• Quality-related risks: because the consumer market is unregulated, contamination, mislabeled potency, or impurities are real concerns independent of the drug itself.
• Unknown: true long-term safety in real-world (non-trial) use, because that data does not yet exist for an unapproved drug.

This is the hub-level summary. A full side-effect deep-dive, including the antibody finding and how to manage GI effects, is a dedicated spoke: cagrilintide side effects and safety deep-dive.

Is cagrilintide safe and legal?

Cagrilintide is not approved by any regulator, so there is no official safety determination, and it is not legal to sell or prescribe as an approved medicine; the products sold to individuals online are unapproved "research chemicals." That investigational status matters more than any single trial result.

On safety, the trial data look reassuring for an investigational drug: side effects are mostly the expected GI ones, and the large Phase 3 program is exactly the kind of testing approval requires. But "reassuring in supervised trials" is not the same as "established safe for self-administration," and long-term real-world safety data simply do not exist for an unapproved compound. On legality, the picture is clear: cagrilintide is investigational and not FDA-approved, on its own or as part of CagriSema. Novo Nordisk filed a U.S. FDA application for CagriSema for weight management on December 18, 2025, based on the REDEFINE 1 and REDEFINE 2 trials, with a regulatory decision expected in 2026; if approved, it would be the first injectable GLP-1-plus-amylin combination (Novo Nordisk / PR Newswire, 2025, retrieved 2026-06-15).

Until that decision, any cagrilintide bought by an individual is an unapproved drug, typically sold "for research use only," outside the regulated supply chain. For the full legal picture and how to evaluate a vendor, see are peptides legal and how to vet peptide quality.

Our take: The single most common misunderstanding is treating the impressive CagriSema trial numbers as if the drug were already available and vetted for general use. It is not. It is investigational, sitting in front of the FDA, and the version sold online is an unapproved research chemical. A strong trial result is not the same as an approved, dispensable medicine.

How do people obtain cagrilintide?

Because cagrilintide is investigational, the only legitimate way to receive it is by enrolling in a clinical trial; outside of that, people buy unapproved "research chemical" vials online, which is a legal and safety gray market. There is no "get a prescription" route for a drug that no regulator has approved.

The two real paths look very different. The legitimate one is a clinical trial: Novo Nordisk's REDEFINE and REIMAGINE programs recruited thousands of participants, who received supervised, quality-controlled drug for free. The other path is the research-peptide market, where vendors sell lyophilized cagrilintide "for research use only" and buyers reconstitute and use it off-label. That market carries real risks of mislabeled potency, impurities, and non-sterile product, with no regulatory oversight (Peptides.org, 2024, retrieved 2026-06-15).

If you are researching that path despite the risks, the responsible groundwork is the same as for any research peptide:

1. Confirm the legal status for your country and situation, including sport and workplace rules. See are peptides legal.
2. Demand a certificate of analysis (COA) from independent third-party testing, and learn to read it for identity and purity. See how to vet peptide quality.
3. Understand handling before anything else. Reconstitution and cold storage are not optional. See getting started with peptides and the peptide injections guide.
4. Talk to a qualified clinician who can weigh your specific health situation, interactions, and contraindications, and wait for a regulated, approved option if you can.

We are describing what people do, not endorsing it. Using an unapproved drug means accepting unknown risks with no regulatory safety net.

Frequently Asked Questions

The bottom line

Cagrilintide is one of the most promising names in the next wave of weight-loss medicine, but it is not a finished product. Its mechanism is genuinely novel for the obesity field: instead of GLP-1, it revives the amylin satiety pathway, and because that pathway is separate, it stacks cleanly with semaglutide. That is the entire logic of CagriSema and the reason a combination reached over 20% weight loss in a large Phase 3 trial.

The other half of the story is discipline. Cagrilintide is investigational, not approved by any regulator, and the version sold online is an unapproved research chemical with no guarantee of what is in the vial. CagriSema is in front of the FDA with a decision expected in 2026, which is exactly the right way for a drug like this to reach people: through trials and regulatory review, not a gray market. If you take one thing from this hub, let it be the gap between "remarkable in a trial" and "approved and dispensable," and the value of waiting for a regulated option and a qualified clinician. From here, the natural next reads are the semaglutide complete guide, how to vet peptide quality, and are peptides legal.

Sources

• The Lancet. "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." 2021. Retrieved 2026-06-15. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)01751-7/abstract
• New England Journal of Medicine. "Coadministered Cagrilintide and Semaglutide in Adults with Overweight or Obesity" (REDEFINE 1). Garvey T, et al. 2025; NEJMoa2502081. Retrieved 2026-06-15. https://www.prnewswire.com/news-releases/cagrisema-2-4-mg--2-4-mg-demonstrated-22-7-mean-weight-reduction-in-adults-with-overweight-or-obesity-in-redefine-1--published-in-nejm-302487770.html
• eBioMedicine / PMC. "Cagrilintide lowers bodyweight through brain amylin receptors 1 and 3." 2025. Retrieved 2026-06-15. https://pmc.ncbi.nlm.nih.gov/articles/PMC12270663/
• Novo Nordisk / PR Newswire. "Novo Nordisk files for FDA approval of CagriSema, the first once-weekly combination of GLP-1 and amylin analogues for weight management." December 18, 2025. Retrieved 2026-06-15. https://www.prnewswire.com/news-releases/novo-nordisk-files-for-fda-approval-of-cagrisema-the-first-once-weekly-combination-of-glp1-and-amylin-analogues-for-weight-management-302645862.html
• Peptides.org. "Cagrilintide | Side Effects, Complications, and Risk Profile." 2024. Retrieved 2026-06-15. https://www.peptides.org/cagrilintide-side-effects-complications-and-risk-profile/
• The Lancet. "Efficacy and safety of co-administered once-weekly cagrilintide 2.4 mg with once-weekly semaglutide 2.4 mg in type 2 diabetes: a phase 2 trial." 2023. Retrieved 2026-06-15. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(23)01163-7/abstract
• Drugs.com. "CagriSema FDA Approval Status." Retrieved 2026-06-15. https://www.drugs.com/history/cagrisema.html