Cagrilintide

Cagrilintide (AM833) is a long-acting, lipidated, albumin-binding amylin analogue with activity at amylin and calcitonin receptors. Lipidation and albumin binding extend the half-life to roughly 7 to 8 days, supporting stable levels on once-weekly subcutaneous dosing.

Endogenous amylin is co-secreted with insulin from pancreatic beta cells and degrades within minutes; cagrilintide substitutes a sustained, supraphysiological signal for that pulsatile one. The axis is entirely separate from the incretin system, which is why combination with a GLP-1 receptor agonist is additive rather than redundant.

Indication is obesity, as monotherapy or combined with a GLP-1 type compound. In REDEFINE 1 (Garvey et al., 2025), CagriSema — cagrilintide 2.4 mg plus semaglutide 2.4 mg — produced 20.4% mean weight loss over 68 weeks, with 60% of participants losing at least 20% and 23% losing at least 30%. Phase 2 monotherapy (Lau et al., 2021) gave 10.8% at the 4.5 mg dose over 26 weeks.

Beyond appetite, the compound is credited with improved circulation, reduced blood pressure, vasodilation, and a bone-building shift in osteoclast/osteoblast activity.

One durability constraint carried on this site from earlier reference material: anti-cagrilintide antibodies have been reported in 46–73% of users with extended exposure, with continuous use capped at 12 weeks under that framing. The REDEFINE-based titration below runs longer and reaches maintenance at week 17, so the two schedules represent different approaches to the same molecule.

Cagrilintide is in Phase 3 trials and is not FDA approved.

Appetite regulation splits across two anatomically and pharmacologically distinct sites. GLP-1 receptor agonism acts in the hypothalamus, modulating homeostatic drive, meal initiation and food noise. Amylin receptor agonism acts in the brainstem, specifically the area postrema, governing meal termination and short-term satiety. Amylin-responsive neurons do not express GLP-1 receptors, so there is no receptor overlap and no competition — the basis for the observed synergy rather than mere addition.

Amylin resistance develops alongside insulin resistance. Compensatory hyperinsulinaemia drives chronically elevated co-secreted amylin, and sustained exposure downregulates amylin receptor signalling. The result is a self-reinforcing loop: blunted satiety, higher intake, worsening insulin resistance, further receptor downregulation. Cagrilintide overcomes this because its signal is both stronger and longer-lived than the pulsatile endogenous ligand.

Secondary mechanisms: delayed gastric emptying prolonging post-prandial fullness, glucagon suppression, and a contribution to glycaemic control that is real but weaker than that of GLP-1 agents.

Half-life of approximately 7 to 8 days gives stable plasma levels on weekly dosing.

The retatrutide case is instructive. Retatrutide targets GLP-1, GIP and glucagon; engineering one molecule for three targets means none is maximised. It is roughly 9 times more potent at GIP but only about 40% as potent at GLP-1 compared with semaglutide, and GLP-1 is the receptor chiefly responsible for appetite suppression — hence stronger residual hunger on retatrutide. Glucagon activation drives hepatic fat oxidation, which is powerful but not something a user feels. Adding cagrilintide supplies a full-strength appetite signal through an untouched system rather than doubling up on an existing one. The cagrilintide–retatrutide pairing has not been studied in clinical trials; the researched combination is cagrilintide plus semaglutide, and the retatrutide pairing rests on mechanism plus what users report.

Appetite and gastric: amylin receptor agonism in the area postrema induces satiety and reduces food intake; delayed gastric emptying prolongs post-prandial fullness. The effect is available to users already on incretin therapy because the receptor populations do not overlap.

Weight outcomes: Phase 2 monotherapy over 26 weeks gave 6.0% at 0.3 mg, 9.0% at 1.2 mg, 9.7% at 2.4 mg and 10.8% at 4.5 mg against 3.0% placebo, with the top dose outperforming liraglutide 3.0 mg (10.8% vs 9.0%). Phase 1b combination over 20 weeks gave 17.1% for cagrilintide 2.4 mg plus semaglutide 2.4 mg against about 10% for semaglutide alone. REDEFINE 1 over 68 weeks: CagriSema 20.4%, semaglutide alone 14.9%, cagrilintide alone 11.5%, placebo 3.0% — 22.7% on full treatment adherence, with 56.4% of CagriSema participants no longer categorised as obese and 88% of those with prediabetes returning to normoglycaemia.

Glycaemic: glucagon suppression plus a direct contribution to glucose control, weaker than GLP-1 agents but real. REDEFINE 2 in 1,206 adults with type 2 diabetes: 13.7% weight loss vs 3.4% placebo, and 73.5% reaching HbA1c ≤6.5% vs 15.9%. The lower weight loss in the T2D population mirrors the pattern across GLP-1 trials.

Vascular: vasodilation with improved circulation and reduced blood pressure.

Skeletal: reduced osteoclast activity with increased osteoblast activity — a net bone-building shift, unusual among weight-loss agents.

Weeks 1 to 4 at 0.25 mg: mild appetite reduction, sometimes barely perceptible. GI effects are usually mild where present. This step is an adaptation phase rather than a therapeutic one.

Weeks 5 to 8 at 0.5 mg: satiety becomes noticeable and portion sizes fall without conscious effort. GI effects may transiently increase with the step up.

Weeks 9 to 16 at 1.0 to 1.7 mg: substantial appetite suppression and a marked drop in food noise. In combination with a GLP-1 compound this is where the dual-pathway effect becomes pronounced, and where protein intake requires active monitoring.

Week 17 onward at 2.4 mg: full therapeutic effect, with consistent suppression and steady loss where nutrition and training are controlled.

The principal failure mode is not tolerability but body composition. Combined amylin and incretin suppression makes chronic underfeeding trivially easy, and insufficient protein intake in a deficit drives lean mass loss alongside fat. The trajectory is rapid early scale movement through weeks 1 to 4, declining strength around months 2 to 3, and a long-term outcome of reduced lean mass, lower metabolic rate and easier regain. Appetite suppression is a tool, not a substitute for intentional intake and training.

Protocol below is the REDEFINE Phase 3 design: subcutaneous, once weekly, fixed day. 0.25 mg for weeks 1–4, 0.5 mg for weeks 5–8, 1.0 mg for weeks 9–12, 1.7 mg for weeks 13–16, then 2.4 mg maintenance from week 17.

The four-week step interval exists to control nausea and GI burden; compressing it is the main cause of dropout. If side effects are marked at any step, hold that dose for a further 4 weeks before escalating. Escalation to 2.4 mg is not obligatory — lower doses produce meaningful responses in some users, and Phase 2 showed 9.0% at 1.2 mg against 9.7% at 2.4 mg, a shallow dose–response at the top end.

Reconstitution. 10 mg vial in 2 mL bacteriostatic water gives 5 mg/mL. Draw volumes: 0.25 mg = 5 units, 0.5 mg = 10 units, 1.0 mg = 20 units, 1.7 mg = 34 units, 2.4 mg = 48 units. At 2.4 mg weekly a 10 mg vial covers approximately 4 weeks. Cagrilintide requires a different pH from most peptides and must not be co-formulated in the same vial.

Combination dosing. Administer separately from semaglutide, tirzepatide or retatrutide — same day is acceptable, different injection sites required. Simultaneous initiation means running both titration schedules independently. Adding cagrilintide to an established GLP-1 protocol means starting at 0.25 mg on the ladder above while holding the incretin dose unchanged. Expect amplified GI effects in combination, particularly during titration, and note that hypoglycaemia risk rises where insulin or sulfonylureas are in play.

Nutrition. Smaller meals during titration, avoiding greasy, fried and spicy foods; ginger tea for nausea. Hydration throughout. Protein target is one gram per pound of body weight daily, prioritised at every meal and tracked — combined amylin plus incretin suppression makes protein underconsumption the default outcome rather than the exception.

Storage. Lyophilised powder at minus 20 degrees Celsius or 2 to 8 degrees Celsius, protected from light. Reconstituted solution refrigerated at 2 to 8 degrees Celsius, used within 28 days, not frozen, discarded if cloudy or discoloured.

Divergent schedule on record. Earlier reference material used on this site runs a faster ladder — 200 mcg, 400 mcg, 750 mcg, 1.2 mg, 1.7 mg, 2.2 mg, then 2.7 mg held for weeks 7–8 — on an 8-week cycle with a 4–8 week washout and a hard cap of 12 consecutive weeks, justified by anti-cagrilintide antibody formation in 46–73% of users on extended exposure. That immunogenicity figure is worth weighing against the REDEFINE schedule, which reaches maintenance only at week 17 and runs continuously.

Cagrilintide (AM833) is a long-acting amylin analogue in Phase 3, not yet FDA approved. It acts at amylin and calcitonin receptors, with the appetite signal routed through the area postrema in the brainstem rather than the hypothalamic axis used by incretins, and the neurons responding to amylin do not carry GLP-1 receptors. Lipidation and albumin binding give a half-life of about 7 to 8 days, supporting stable levels on once-weekly dosing. Slowed gastric emptying, glucagon suppression and a net bone-building shift — reduced osteoclast with increased osteoblast activity — plus vasodilation, improved circulation and reduced blood pressure are also attributed to it.

Phase 2 monotherapy (Lau DCW et al., The Lancet, 2021): 706 participants with obesity, 26 weeks. Weight loss 6.0% at 0.3 mg, 9.0% at 1.2 mg, 9.7% at 2.4 mg, 10.8% at 4.5 mg, 3.0% placebo; 4.5 mg outperformed liraglutide 3.0 mg (10.8% vs 9.0%). Earlier summaries give 6–10% at 26 weeks as monotherapy.

Phase 1b combination (Enebo LB et al., The Lancet, 2021): 20 weeks, cagrilintide 2.4 mg plus semaglutide 2.4 mg produced 17.1% weight loss versus approximately 10% for semaglutide alone.

REDEFINE 1 (Garvey WT et al., NEJM, 2025): 3,417 adults without diabetes, 68 weeks. CagriSema 20.4%, semaglutide alone 14.9%, cagrilintide alone 11.5%, placebo 3.0%; 60% achieved ≥20% loss and 23% ≥30%; 22.7% under full treatment adherence; 56.4% no longer categorised as obese; 88% of those with prediabetes returned to normoglycaemia. Earlier reporting of the combination gives 23–24.4% at 68 weeks and up to 8% additional loss over semaglutide alone.

REDEFINE 2 (Davies MJ et al., NEJM, 2025): 1,206 adults with type 2 diabetes, 68 weeks. CagriSema 13.7% versus placebo 3.4%; HbA1c ≤6.5% in 73.5% versus 15.9%. The attenuated weight response in T2D is consistent across the incretin trial literature.

Mechanistic development work is covered by Kruse T et al., Journal of Medicinal Chemistry (2021). The clinical evidence base is cagrilintide plus semaglutide; cagrilintide with tirzepatide or retatrutide has not been trialled and rests on the absence of receptor overlap between amylin and GLP-1, GIP or glucagon.

The other durability constraint is immunogenicity: anti-cagrilintide antibodies in 46–73% of users on extended exposure.