Cagrilintide

Plain-English version: cagrilintide is a man-made copy of a hormone called amylin, re-engineered so a single injection keeps working for a whole week. Amylin is one of your body's natural "I'm full" signals — your pancreas releases it alongside insulin every time you eat.

Native amylin (also called islet amyloid polypeptide, or IAPP) is a 37-amino-acid hormone. In the body it does three main jobs: it slows how quickly food leaves your stomach, it tells your brainstem you have eaten enough, and it tames the after-meal rise of glucagon (a hormone that pushes blood sugar up). The problem for drug developers is that natural amylin breaks down almost immediately and tends to clump together, so it is useless as a once-weekly medicine.^[1]

Cagrilintide solves that with two engineering tricks: amino-acid substitutions that stop the molecule from aggregating, and a fatty-acid "tail" (acylation) that lets it ride along on blood albumin, dramatically stretching its half-life. The result is a stable amylin analog that can be dosed once a week under the skin. For context, the first-generation amylin drug pramlintide (Symlin), which is FDA-approved for diabetes, has to be injected before every meal — cagrilintide is a major convenience leap over it.^[2]

The credibility point, stated up front: cagrilintide is developed by Novo Nordisk essentially as one component of CagriSema, a fixed-dose combination that pairs cagrilintide 2.4 mg with semaglutide 2.4 mg in a single weekly shot. There is no approved standalone cagrilintide product anywhere. Novo Nordisk submitted a New Drug Application for CagriSema to the U.S. FDA in December 2025, based on the phase 3 REDEFINE program, with an FDA decision expected during 2026.^[4] Until then, any therapeutic use is limited to clinical-trial participants. For the broader legal picture, see Are Peptides Legal?

Takeaway first: cagrilintide turns up your body's natural fullness signal so you eat less without white-knuckling it. It does this through the amylin/calcitonin receptor system — a completely different pathway from GLP-1 drugs, which is exactly why the two get combined.

1. Satiety signaling in the brainstem (the core mechanism)

Cagrilintide is a non-selective agonist at amylin receptors (AMY1, AMY2, AMY3), which are built from the calcitonin receptor paired with receptor-activity-modifying proteins (RAMPs). Its most important action is in the area postrema and nucleus tractus solitarius — brainstem regions that read hormonal "fullness" signals and reduce food intake. In plain terms, it makes your brain register that you have eaten enough, sooner and for longer.^[1] Evidence level: human pharmacology and clinical trials.

2. Slowed gastric emptying

Amylin agonism slows the rate at which the stomach hands food off to the small intestine. Food stays in the stomach longer, which prolongs the sensation of fullness and blunts the after-meal blood-sugar spike. This is also the mechanism behind much of the early nausea people report — the stomach is literally moving more slowly than usual.^[1]

3. Suppression of after-meal glucagon

Glucagon is a hormone that raises blood sugar. In some people its post-meal release is inappropriately high. Amylin signaling reins that in, which helps flatten glucose swings — one reason cagrilintide has been studied in type 2 diabetes, not just obesity.^[3]

4. Why it is combined with GLP-1 (the CagriSema rationale)

Semaglutide works through the GLP-1 receptor; cagrilintide works through the amylin receptor. These are two separate appetite-control systems, so stacking them is additive rather than redundant — you are pressing two different "eat less" buttons at once. A phase 1b study in healthy overweight adults first proved the two could be co-administered safely with no unexpected drug-interaction or pharmacokinetic surprises, which is the finding that seeded the entire CagriSema program.^[2] Evidence level: human phase 1b trial.

What we do NOT yet know

The long-term consequences of sustained amylin-receptor activation in humans — over many years — are not fully characterized, because the longest pivotal trial ran 68 weeks. How cagrilintide behaves in people with significant kidney or liver impairment has not been established either. The mechanisms above are grounded in real human trials, but "well understood over 68 weeks" is not the same as "understood over a decade."

How to read this section: for each area we give the plain-English claim, the mechanism, the population actually studied, the effect size, and the limitation. Unlike most peptides on this site, the evidence base here is human — phase 2 and phase 3 randomized controlled trials in thousands of people. That is a meaningfully higher tier of evidence, and we flag where the numbers come from.

Weight loss — cagrilintide alone

Claim: once-weekly cagrilintide produces clinically meaningful weight loss by itself. Mechanism: amylin-driven satiety plus slowed gastric emptying. Population: 706 adults with overweight or obesity, without diabetes, in a 26-week phase 2 dose-finding trial (Lau 2021). Effect: a clear dose-response, with the top 4.5 mg dose producing roughly 10.8% mean body-weight loss versus about 3.0% on placebo — and numerically edging out the active comparator, liraglutide 3.0 mg (~9.0%).^[1] Limitation: 26 weeks is relatively short, and this is monotherapy, which is not how cagrilintide is being brought to market.

Weight loss — CagriSema combination

Claim: pairing cagrilintide with semaglutide beats either drug alone. Mechanism: additive amylin + GLP-1 appetite suppression. Population: 3,417 adults with overweight or obesity and at least one weight-related complication, without diabetes, in the 68-week phase 3 REDEFINE 1 trial (Garvey, Blüher, et al.). Effect: mean weight change with CagriSema was -20.4% versus -3.0% for placebo under the treatment-policy estimand reported in the New England Journal of Medicine, and -22.7% under the on-treatment (trial-product) estimand widely cited by Novo Nordisk.^[4] Limitation: those two numbers answer slightly different questions — the treatment-policy figure counts everyone regardless of whether they stayed on the drug, while the on-treatment figure describes people who kept taking it as directed. Both are legitimate; they should not be conflated, and the lower, more conservative -20.4% is the headline efficacy number from the published paper.

Blood-sugar control in type 2 diabetes

Claim: CagriSema improves both weight and glucose in people with diabetes. Mechanism: amylin-driven glucagon suppression and satiety layered onto GLP-1 action. Population: adults with type 2 diabetes (BMI ≥27) on metformin with or without an SGLT2 inhibitor, in a 32-week phase 2 trial (Frias 2023). Effect: CagriSema produced significantly greater weight loss than semaglutide 2.4 mg or cagrilintide 2.4 mg alone, while delivering HbA1c (a three-month blood-sugar average) improvement comparable to semaglutide on its own.^[3] Limitation: phase 2, 32 weeks, and glycemic benefit came largely from the semaglutide component rather than cagrilintide adding much on top for blood sugar specifically.

The honest bottom line on "benefits"

• The evidence is human and randomized — a real strength versus animal-only peptides — but the longest pivotal data run is 68 weeks, so multi-year durability and safety are still open questions.
• Standalone cagrilintide is not the product. Almost all late-stage development is the CagriSema combination, so "cagrilintide benefits" in practice usually means "CagriSema benefits."
• Estimand literacy matters. Headlines quoting "22.7%" and papers quoting "20.4%" are describing the same trial with different analytical rules — neither is wrong, but they are not interchangeable.
• None of this is FDA-approved yet. Efficacy in a trial is not the same as an available, regulated medicine.

Read this first: the doses below come from published human clinical-trial protocols, not from a marketed, approved label — because cagrilintide is not approved. We describe them for understanding, not as instructions to self-administer an investigational drug.

Doses studied in the trials

Setting	Cagrilintide dose	Route	Frequency	Source
Monotherapy (phase 2 dose-finding)	0.3–4.5 mg (escalated)	Subcutaneous	Once weekly	Lau 2021
CagriSema combination (phase 2/3)	2.4 mg cagrilintide + 2.4 mg semaglutide	Subcutaneous	Once weekly	Frias 2023; REDEFINE 1

The single most important dosing principle is gradual escalation. In the phase 2 monotherapy trial, cagrilintide was titrated upward over several weeks rather than started at full strength, specifically to limit the nausea and other gut effects that peak early.^[1] In CagriSema, both components are stepped up together toward the 2.4/2.4 mg target dose over a titration period.^[3]

How the clinical formulation is delivered

Cagrilintide is given as a subcutaneous injection — the same fat-pad injection technique used for semaglutide. In CagriSema, both peptides are combined in a single pre-filled injection device, so there is one shot, not two, and no mixing or reconstitution on the patient's end. It is taken on the same day each week, at any time of day, with or without food.

A note on reconstitution math (for research-market powder)

The approved-style CagriSema pen is pre-filled, so no math is required there. The unregulated "research" cagrilintide sold as a lyophilized (freeze-dried) powder is a different, unverified product — but since people encounter reconstitution questions, here is the underlying formula and a worked example so the arithmetic is transparent:

Concentration (mg/mL) = vial amount (mg) ÷ water added (mL)

Worked example: a 5 mg vial reconstituted with 2 mL of bacteriostatic water gives 5 ÷ 2 = 2.5 mg/mL (2,500 mcg per mL). To draw the 2.4 mg trial dose: 2,400 ÷ 2,500 = 0.96 mL, which is 96 units on a standard 100-unit insulin syringe. You can check volumes with the peptide calculator and bacteriostatic water calculator, and follow the reconstitution guide for technique. We are describing the arithmetic, not endorsing self-dosing an investigational compound from an unregulated source.

Cycle length and timing

• Duration: the pivotal trials ran continuously — 26 weeks (monotherapy), 32 weeks (T2D), and 68 weeks (REDEFINE 1). This is a chronic, ongoing-treatment paradigm like other GLP-1-class obesity drugs, not a short "cycle."
• Titration window: expect the first several weeks to be a stepped dose-escalation phase where side effects are most likely.
• Timing: once weekly, same day, any time of day; no meal timing is required.

None of the above is a recommendation to self-administer. It is a description of how the research doses are structured. See peptides for weight loss for how this fits the broader class.

Straight talk: cagrilintide's side-effect profile is dominated by gut symptoms — nausea, vomiting, diarrhea, constipation — that are usually mild to moderate, peak while the dose is being escalated, and decline over time. This is the same family of effects seen across the GLP-1/incretin class. Across the reported trials, no unexpected serious safety signal was identified.^[1][3][4]

Reported side effects (from human trials)

Effect	Pattern	Notes
Nausea	Most common	Peaks during dose titration; eases with stable dosing
Vomiting	Dose-dependent	More common at higher doses and in combination therapy
Diarrhea	Common	Usually mild to moderate and transient
Constipation	Common	Related to slowed gastric motility
Decreased appetite	Expected	The intended pharmacological effect, not an adverse event per se
Injection-site reactions	Uncommon, mild	Transient
Discontinuation from adverse events	Dose-dependent	Mostly GI-driven; in the same range as semaglutide monotherapy

A key finding for the combination: pairing cagrilintide with semaglutide produces additive, not synergistic, gut burden — roughly the sum of each drug's individual effects rather than an unexpected amplification.^[3] In REDEFINE 1, most adverse events were mild to moderate and lessened over time.^[4]

Amylin-pathway and class considerations

• Substantial gastric-emptying delay can, in theory, alter the absorption of oral medications taken at the same time — relevant for narrow-therapeutic-index drugs.
• Hypoglycemia (low blood sugar) is uncommon with cagrilintide as monotherapy in people without diabetes, but the risk rises sharply when it is combined with insulin or sulfonylureas.
• Dehydration-related kidney injury is a class concern: severe nausea and vomiting can cause volume loss and, secondarily, acute kidney injury — a fluid problem, not direct drug toxicity to the kidney.
• Long-term effects of sustained amylin-receptor agonism in humans are not fully characterized beyond the 68-week pivotal trial horizon.

Who should be cautious or avoid it

• Personal or family history of medullary thyroid carcinoma or MEN 2: the GLP-1-class boxed warning is generally applied to the semaglutide component of CagriSema as a precaution — discuss with a prescriber.
• Recurrent pancreatitis or severe GI disease (e.g. gastroparesis): pancreatitis is a class warning; new persistent severe abdominal pain warrants stopping and evaluation.
• Pregnancy and breastfeeding: not established as safe — avoid.
• Insulin or sulfonylurea users: dose adjustments may be needed to avoid hypoglycemia.

For broader context, see Are Peptides Safe? and Peptide Side Effects.

The limitations to keep in mind

• The longest safety dataset is 68 weeks; multi-year safety is not yet established.
• Cagrilintide is investigational — a full approved-drug safety label does not yet exist.
• Research-market cagrilintide is unregulated and is not the clinical-grade molecule the trials studied, so its safety cannot be inferred from the trial data at all.

Why this section matters: there is a hard line between the cagrilintide studied in Novo Nordisk's trials and the "cagrilintide" sold in research-peptide markets. The former is a tightly controlled clinical-grade molecule available only through trials; the latter is an unregulated product of unknown identity and purity. They should not be treated as the same thing.

Legal and regulatory status (2026)

• Not FDA-approved: there is no approved standalone cagrilintide product anywhere in the world. It is investigational.
• CagriSema under FDA review: Novo Nordisk submitted a New Drug Application for the CagriSema combination (cagrilintide 2.4 mg + semaglutide 2.4 mg) to the FDA in December 2025, based on the phase 3 REDEFINE program; an FDA decision is expected during 2026.^[4]
• Trial-only access: until any approval, legitimate use is restricted to clinical-trial participants.
• Research-market product is unregulated: cagrilintide sold as "research peptide" is not the clinical-grade molecule used in the trials, and no regulator vouches for it.

What a credible research product would show

• Third-party Certificate of Analysis (COA): independent HPLC purity testing plus mass-spectrometry identity confirming the expected molecular structure.
• Batch-specific results: the COA should reference the exact lot, not a generic sample.
• Endotoxin (LAL) testing: essential for anything intended to be injected.
• Proper form and packaging: lyophilized powder in a sealed, light-protected vial.

Red flags

• No COA, or a COA issued by the seller rather than an independent lab
• Pre-mixed "ready to use" liquid (shorter shelf life, contamination risk)
• Prices far below market
• Explicit human-use or medical claims, which signal a non-compliant vendor

Storage

Clinical formulations are refrigerated at 2–8°C, kept from freezing, and protected from light. Lyophilized research powder should be kept cold and dark; once reconstituted, refrigerate and use within a few weeks, never freeze the solution, and discard anything cloudy or discolored. See the full peptide storage guide and Are Peptides Legal? for the complete legal picture.

Cagrilintide is almost always discussed alongside the GLP-1-class drugs, both because of the CagriSema pairing and because they compete for the same clinical territory. None of these are head-to-head trials against cagrilintide monotherapy — they contrast mechanisms and each drug's own trial results. For a full overview of the class, see the complete GLP-1 guide.

• Semaglutide (Ozempic/Wegovy): the GLP-1 agonist paired with cagrilintide in CagriSema. On its own it delivers meaningful weight loss; combined with cagrilintide, the phase 3 REDEFINE 1 result rose to roughly 20% under the published estimand.^[4]
• Tirzepatide (Mounjaro/Zepbound): a dual GLP-1/GIP agonist — a different multi-pathway strategy than CagriSema's amylin + GLP-1 approach.
• Retatrutide: a triple GLP-1/GIP/glucagon agonist representing yet another multi-target design.
• Survodutide and mazdutide: dual GLP-1/glucagon agonists that add energy expenditure and liver-fat benefits through glucagon activation.
• Liraglutide (Saxenda): the first-generation daily GLP-1 agonist and the active comparator that cagrilintide monotherapy numerically outperformed in phase 2.^[1]