Cagrilintide: the weekly amylin shot, what the trials show, and where it stands

Cagrilintide is a lab-made, long-acting version of amylin, a hormone your pancreas releases with every meal to tell your brain you have eaten enough ⁶. A fatty side chain lets it last about a week in the body, so trial participants injected it once weekly ². It has been tested in adults with obesity or overweight, with and without type 2 diabetes. Cagrilintide works through a different signal from semaglutide, so the two drugs add up when given together, and that pairing is where most of the trial data sits.

What amylin does, and why drugmakers copy it

Amylin is a small hormone made by the same pancreatic beta cells that make insulin, and the two are released together after a meal ⁶. Insulin moves sugar out of the blood. Amylin works on appetite and digestion: it signals fullness to the brain, slows how fast the stomach empties, and suppresses the release of glucagon (a hormone that raises blood sugar) after eating ⁶. In both type 1 and type 2 diabetes, the pancreas releases less insulin and less amylin after meals ⁶.

Natural human amylin makes a poor drug because it tends to clump into insoluble fibers. Pramlintide, the first amylin drug, fixed that with three amino-acid swaps, but it lasts under an hour, so people inject it before every main meal ⁶. Cagrilintide carries a fatty-acid chain that binds to <a href="/biomarkers/albumin-serum">albumin</a> (the main protein in blood plasma), which slows its clearance to a half-life of about 159 to 195 hours, roughly a week ².

How cagrilintide differs from a GLP-1 drug

Semaglutide copies GLP-1, a gut hormone. Cagrilintide copies amylin, a pancreatic hormone, and switches on amylin receptors plus a close cousin, the calcitonin receptor (normally the target of calcitonin, a hormone from the thyroid gland) ¹. Both drugs reduce appetite, but they reach the brain through separate receptors. When the trials compared them side by side, the combination beat either drug alone ⁴.

Cagrilintide on its own

Drug trials run in phases: Phase 1 checks safety in small groups, Phase 2 finds the dose, and Phase 3 tests it in thousands of people before approval. The first large cagrilintide trial, a Phase 2 study, gave 706 adults with overweight or obesity and no diabetes one of five weekly doses (0.3 to 4.5 mg), daily liraglutide 3.0 mg, or placebo for 26 weeks ¹. Weight loss rose with the dose. At the top dose, average weight loss was 10.8%, compared with 9.0% on liraglutide and 3.0% on placebo ¹. Liraglutide is an older, daily GLP-1 drug, so cagrilintide matched or slightly beat an approved obesity medicine over six months.

Treatment with cagrilintide in people with obesity and overweight led to significant reductions in bodyweight and was well tolerated.Lau DCW et al., The Lancet, 2021 ¹

The longer test came inside REDEFINE 1, a Phase 3 trial where one group took cagrilintide 2.4 mg alone for 68 weeks. That group lost 11.8% of body weight on average, against 14.9% for semaglutide 2.4 mg alone ⁴. Cagrilintide works, but on its own it is a weaker weight-loss drug than semaglutide.

CagriSema: cagrilintide plus semaglutide

CagriSema is both drugs at 2.4 mg, given once a week. In a 20-week Phase 1b trial, the pair produced 17.1% average weight loss versus 9.8% for semaglutide with placebo ². In a 32-week Phase 2 trial in type 2 diabetes, CagriSema lowered HbA1c by 2.2 points, for example from 8.2% to 6.0% (1.8 with semaglutide, 0.9 with cagrilintide), and body weight by 15.6% (5.1% with semaglutide, 8.1% with cagrilintide) ³. If you are unsure how HbA1c and fasting glucose differ, see <a href="/compare/a1c-vs-fasting-glucose">A1c vs fasting glucose</a>.

REDEFINE 1 enrolled 3,417 adults with obesity and no diabetes for 68 weeks. Average weight change was -20.4% on CagriSema and -3.0% on placebo, with -11.8% for cagrilintide alone and -14.9% for semaglutide alone ⁴. REDEFINE 2 enrolled 1,206 adults with obesity and type 2 diabetes: -13.7% on CagriSema against -3.4% on placebo, and more people reached an HbA1c of 6.5% or lower ⁵. People with type 2 diabetes typically lose less weight on obesity drugs than people without it, so the smaller number in REDEFINE 2 is in line with that pattern.

Side effects and who should be careful

Cagrilintide's side effects are mostly digestive. In the Phase 2 trial the most common were nausea, constipation and diarrhea, plus injection-site reactions, and most were mild to moderate ¹. In REDEFINE 1, about 80% of people on CagriSema had a gastrointestinal side effect versus about 40% on placebo, mostly short-lived and clustered around dose increases ⁴. As with other weight-loss drugs in this class, rapid weight loss raises the chance of gallstones. The longest published trials ran 68 weeks, so data beyond about a year and a half do not yet exist.

The pramlintide label rules out use in gastroparesis (a slow-emptying stomach) and in people who cannot feel their own low blood sugars ⁶. Cagrilintide acts on the same pathway, and these groups have no cagrilintide trial data to go on. The same is true for anyone pregnant or breastfeeding.

Is cagrilintide FDA-approved, and when will it be available?

No approval date has been set. Cagrilintide is not approved anywhere, alone or as CagriSema. Novo Nordisk announced in December 2025 that it had filed CagriSema with the FDA for weight management, and no approval had been announced as of November 2026. Cagrilintide on its own is still being studied. Until approval, the only legitimate way to receive cagrilintide is inside a registered clinical trial, and because there is no approved product, US compounding pharmacies generally have no legal route to make it. Anyone weighing a weight-loss medicine can ask their clinician whether an approved option such as semaglutide fits them, or whether a cagrilintide trial is recruiting nearby (trials are listed on ClinicalTrials.gov).

Other amylin drugs in development

Petrelintide, from Zealand Pharma and Roche, is another long-acting amylin analog in trials. Amycretin, from Novo Nordisk, is a single molecule built to act on both GLP-1 and amylin receptors, combining in one peptide what CagriSema does with two. Both are investigational.

What to watch on your blood tests on an amylin or GLP-1 drug

For people with type 2 diabetes, HbA1c and fasting glucose usually fall on these drugs, as the 2.2-point HbA1c drop in the CagriSema diabetes trial showed ³; if your fasting glucose is still above range, see <a href="/biomarkers/glucose-fasting/high">high fasting glucose</a>. Triglycerides and <a href="/learn/liver-enzymes-explained">ALT</a> (a liver enzyme that runs high in fatty liver) often improve as weight comes off. Eating much less for months can lower vitamin B12 and <a href="/learn/iron-studies-explained">ferritin</a> (stored iron), and <a href="/compounds/metformin">metformin</a> is known to lower B12 on its own. A <a href="/learn/kidney-function-explained">creatinine</a> rise after days of vomiting points to dehydration. Clinicians usually check lipase when stomach pain raises the question of pancreatitis, not as a routine screen.

A practical plan to raise with your clinician: HbA1c, fasting glucose, a lipid panel, ALT, creatinine, B12 and ferritin before starting, then again about 3 months in and every 6 to 12 months after, or sooner after days of vomiting. Clinicians often check B12 at least yearly in people who also take metformin. Any result outside its reference range, or one that changes sharply on treatment, is one to go over with the clinician running your care or trial.

Every large weight loss takes some muscle with the fat, and that applies to cagrilintide as much as any other drug. Protein intake and resistance training are the two habits linked to keeping more lean mass while appetite is low. To track it, the <a href="/calculators/lean-body-mass">lean body mass calculator</a> gives a rough starting number.

CalculatorProtein calculatorSee how much protein a day fits your weight while eating less.Work it out

For the wider picture on weight and metabolic health, see the guides to <a href="/for/weight-loss">weight loss</a>, <a href="/conditions/type-2-diabetes">type 2 diabetes</a>, <a href="/conditions/insulin-resistance">insulin resistance</a>, <a href="/conditions/prediabetes">prediabetes</a>, <a href="/conditions/fatty-liver">fatty liver</a>, <a href="/learn/blood-sugar-explained">how blood sugar works</a> and <a href="/learn/metabolic-panel-explained">what a metabolic panel shows</a>. To check for insulin resistance before or during treatment, use the <a href="/calculators/homa-ir">HOMA-IR calculator</a> with your <a href="/biomarkers/fasting-insulin">fasting insulin</a>.

Free, no accountDrop in your lab report and see every marker explained in plain words, placed on the body, against your lab's range. It's read on your device: nothing is uploaded and nothing is kept.

Read my results Download the app