Cagrilintide is a synthetic, lipidated analog of amylin — the 37-residue peptide hormone of the pancreatic β-cell [8], coexpressed there with insulin [7]. It belongs to a class of research compounds described in the literature as dual amylin and calcitonin receptor agonists, or DACRAs, and it is one of the better-characterized members of that class: its receptor pharmacology has been profiled across dozens of endpoints [2], and cryo-EM structures of the peptide bound to two of its target receptors have been published [3]. This guide covers what the primary literature documents — verified chemical identity, the receptor architecture the molecule acts on, the structural work on how it engages that architecture, and the model systems in which amylin signaling has been characterized. It also marks where the record is thin. Cagrilintide is supplied for in-vitro research use only.

Verified identity

The identity data below is the same data carried on the product page, and it comes from a public chemical record rather than from a supplier datasheet:

That molecular weight is the number the reconstitution table on the product page is calculated from, which is why the figures there are internally consistent: 10 mg of lyophilized powder taken up in 1 mL is 10 mg/mL, and 10 mg divided by 4409.1 g/mol is 2.268 µmol, which in 1 mL is 2.27 mM. Reconstitution does not change the mass in the vial, only the volume it occupies, so the concentration is set entirely by the diluent volume.

Two structural details are worth reading off the formula. The mass, at roughly 4.4 kDa, is well above the ~3.9 kDa of unmodified human amylin, which is consistent with the acylation the molecule carries. And the two sulfur atoms are consistent with the single intramolecular disulfide that the amylin scaffold carries near its N-terminus; there are no methionines to account for them. Neither observation is a substitute for the published structure, and neither should be treated as an independent measurement.

Why an amylin analog had to be engineered at all

Human amylin is a difficult starting scaffold. Its defining biophysical property is a strong propensity to form amyloid fibrils, which the group that developed cagrilintide described as making it a challenging drug design effort [1]. The earlier amylin analog pramlintide is commercially available, but the same account notes that it has a short half-life [1]. The design work that produced cagrilintide targeted both properties at once — a stable, lipidated, long-acting analog — and the published account is a structure-activity study across a series of analogs from which this one was selected [1].

The lipidation is the protraction strategy. Fatty-acid modification of peptides is generally understood to work by promoting reversible binding to circulating albumin, which slows clearance, though none of the cagrilintide papers cited here measure that binding directly. The structural paper on cagrilintide notes, in passing, that other compounds in the DACRA class achieve extended half-life primarily through N-terminal lipid modification, and treats cagrilintide's binding mode as distinct from theirs [3]. That is a comparison of binding modes, not a claim about relative half-lives, and it should not be read as one.

The receptors: a core GPCR plus an accessory protein

Amylin does not have a dedicated receptor gene. Its receptors are heterodimers assembled from the calcitonin receptor (CTR), a class B G protein-coupled receptor, and one of three receptor activity-modifying proteins (RAMPs) [4, 8]. That architecture was shown directly in cotransfection experiments in COS-7 cells: coexpressing RAMP1 or RAMP3 with a human calcitonin receptor isoform induced specific binding of radiolabeled rat amylin, while RAMP2 or empty-vector cotransfection did not produce a significant increase in that system [5]. The RAMP1- and RAMP3-derived receptors were not equivalent to each other — competition binding revealed two distinct phenotypes, and while the RAMP3-derived receptor showed affinities for amylin and the calcitonins similar to those of the RAMP1-derived one, the authors reported that the efficacy of human α-CGRP was markedly reduced [5]. The authors concluded that for the calcitonin receptor family, and potentially for other class B GPCRs, the cellular phenotype is likely to be dynamic with respect to the levels and combinations of receptor and RAMP present [5].

By current nomenclature the three complexes are AMY1R (CTR + RAMP1), AMY2R (CTR + RAMP2) and AMY3R (CTR + RAMP3) [4]. This matters for interpreting any assay result involving cagrilintide, because "the amylin receptor" is not one target. A cell line expressing CTR alone, a cell line expressing CTR with one RAMP, and a native tissue expressing several in unknown ratios are three different pharmacological systems.

RAMPs change signaling, not just binding

The accessory protein is not merely a chaperone that confers amylin affinity. Alanine-scanning mutagenesis of extracellular loops 2 and 3 of the calcitonin receptor, performed with and without RAMP3 coexpression, showed that the contribution of those loops to propagating signal — measured as cAMP accumulation and ERK phosphorylation — is fundamentally altered when the receptor is complexed with RAMP3 to form AMY3R, even though only ECL2 was predicted to make direct contact [7]. The effect of a given mutation depended heavily on which peptide was being tested, across salmon, human and porcine calcitonin, rat amylin and human α-CGRP. The authors drew the conclusion that even subtle changes to peptide sequence may change signaling output downstream of the receptor [7]. For an engineered analog, that is the central caveat: potency and bias at these receptors are not reliably predictable from the parent hormone's behavior.

What the structures show

Structures of the amylin receptors themselves were reported in 2022, covering active amylin receptors — amylin bound to all three AMYRs, salmon calcitonin bound to AMY1R, salmon or human calcitonin bound to AMY2R, and CTR bound to amylin, salmon calcitonin or human calcitonin [4]. The amylin-bound complexes adopted a similar conformation across all three AMYRs, constrained by the RAMP, with an ordered midpeptide element the authors named the bypass motif. The calcitonin-bound AMYR complexes were distinct and overlapped the calcitonin-bound CTR complexes instead, which led the authors to conclude that activation of amylin receptors by calcitonin-based peptides is distinct from their activation by amylin-based peptides [4].

Cagrilintide itself was later resolved by cryo-EM in complex with AMY1R-Gs and with CTR-Gs [3]. The peptide adopted similar bypass-mode binding in both receptors. The authors identified three features they proposed as enabling this non-selective engagement: residue F23 anchoring the peptide at the level of the transmembrane bundle and the micelle, an intramolecular E14–R17 salt bridge that they described as enhancing helical stability, and a C-terminal P37 contact with the receptor extracellular domain [3]. Their structural and functional analyses together indicated non-selective activation of Gs signaling through both CTR and AMY1R [3]. Structures for AMY2R and AMY3R in complex with cagrilintide were not part of that study.

Receptor pharmacology of cagrilintide specifically

The most detailed published pharmacological characterization compared cagrilintide — under its development code AM833 — against six other agonists across 25 endpoints spanning receptor binding, activation and regulation [2]. The comparator set was chosen to bracket the selectivity axis: amylin-receptor-selective and non-selective lipidated analogs, pramlintide as an AMYR-selective peptide, salmon calcitonin as a non-selective one, and human calcitonin and rat amylin as prototypical selective agonists of CTR and the AMYRs respectively [2]. The finding the authors reported is that cagrilintide has a pharmacological profile distinct from all of them across those diverse measures, and they framed the work as providing mechanistic insight into its actions rather than as establishing a single potency ranking [2]. The compound is characterized there as a non-selective agonist of both amylin receptors and the calcitonin receptor [2].

A methodological limitation runs underneath all of this. Until recently there was no direct, subtype-selective functional assay for the individual amylin receptors [6]. An assay built on luciferase fusion to CTR or to individual RAMPs, reading recruitment of Venus-tagged Gs, was developed to resolve this and revealed a pattern of receptor activation by calcitonin, amylin and DACRA peptides that was distinct at each receptor subtype [6]. In that study, two calcitonin-based DACRAs behaved similarly at CTR and AMY1R but generated distinct responses at AMY2R and AMY3R [6]. The relevance here is that subtype-resolved data is the standard newer work is held to, and much of the older amylin literature predates the tools to generate it.

Where amylin signaling is read in the brain

Amylin acts principally in the circumventricular organs of the central nervous system, and functionally interacts with other metabolically active hormones including cholecystokinin, leptin and estradiol [8]. The principal peripheral binding site is the area postrema, from which the signal propagates to the nucleus of the solitary tract and the lateral parabrachial nucleus, and onward to forebrain regions including the central amygdala and the bed nucleus of the stria terminalis [9]. A separate arcuate-nucleus route has been described that appears to act independently of the area postrema, engaging POMC and NPY neurons; in that account, amylin activation of NPY neurons is transmitted to lateral parabrachial neurons and relates to eating, while POMC signaling relates to energy expenditure and locomotor activity [9]. The authors of that review were explicit that how amylin reaches forebrain areas remains to be worked out [9].

Two experimental results give this circuitry more than descriptive weight. First, blocking the receptor changes behavior in the expected direction: the amylin receptor antagonist AC187 attenuated amylin's inhibition of food intake in rats by roughly half, and administered alone it increased food intake in a dose-dependent manner, along with mean meal size and meal frequency [11]. The authors reported that these results support the hypothesis that endogenous amylin plays an essential role in reducing meal size and increasing the postmeal interval [11] — a hypothesis-supporting result, and stated as such. Second, amylin appears to remodel the tissue it acts on. In adult rats, amylin upregulated the NeuroD1 transcript and protein in the area postrema, an effect blocked by co-administration of AC187, and chronic exposure increased the number of newly proliferated area postrema cells and promoted their differentiation into neurons rather than astrocytes [10]. That study was performed with amylin, not with cagrilintide.

Peripheral endpoints

Two peripheral effects are commonly attributed to amylin signaling, and the evidence behind them differs in strength.

Gastric emptying. Amylin inhibits gastric emptying in rats, and a comparative study of amylin-related peptides found that salmon calcitonin, rat CGRP and rat adrenomedullin all inhibited both food intake and gastric emptying with distinct potencies, while rat calcitonin was not effective on food intake at the doses tested [12]. The authors' stated conclusion was that these results suggest amylin and salmon calcitonin may act by a common mechanism to decrease food intake, one that includes inhibition of gastric emptying [12]. The modal verbs are theirs.

Glucagon. This one is more constrained than it is often reported to be. In isolated perfused rat pancreas, amylin had no effect on arginine-, carbachol- or VIP-stimulated glucagon secretion, and it had no effect in isolated islets stimulated with arginine even though somatostatin inhibited secretion in the same preparation [13]. In anesthetized rats, however, amylin inhibited arginine-induced glucagon secretion but not hypoglycemia-induced glucagon secretion in the same animal [13]. The authors identified this as a selective glucagonostatic effect that appears to be extrinsic to the isolated pancreas, and noted it may be centrally mediated [13]. "Amylin suppresses glucagon" is therefore too coarse a summary: the effect was stimulus-selective and absent in the isolated organ.

Combination pharmacology

Because amylin and GLP-1 receptor agonists engage different receptors, combination work is an active research area, and the possibility of additive action with GLP-1 receptor agonists is noted in the receptor pharmacology literature [2]. The most informative preclinical result is an energy-balance study in rats of cagrilintide combined with the GLP-1 analog semaglutide [14]. Rats given the combination showed a 12% reduction in body weight alongside a 39% reduction in food intake. Pair-feeding produced a less pronounced reduction in body weight, and matching the body-weight change by food restriction alone required a 51% decrease in intake. The authors' inference from that arithmetic was that approximately one-third of the combination's effect arises from an action on energy expenditure — a blunting of the metabolic adaptation that normally accompanies reduced intake [14]. This is a rodent energy-balance finding under controlled feeding, and its value is in the mechanistic decomposition rather than in the magnitude.

What is not established

Several gaps are worth stating plainly, because they shape what an experiment using this compound can conclude.

  • Subtype selectivity is only partly mapped. The published cagrilintide structures cover AMY1R and CTR, and complexes with AMY2R or AMY3R were not part of that study [3]. A directly subtype-selective functional assay able to resolve activity at AMY2R and AMY3R has been described [6], and that is the resolution any subtype-level claim about cagrilintide would need to meet.
  • Most circuit-level work used amylin, not cagrilintide. The area postrema, arcuate and parabrachial findings cited above were generated with the native hormone or with antagonists of it [9, 10, 11]. Given how strongly RAMP context and peptide sequence shape signaling output [7], transferring those results to a lipidated analog is an assumption, not a finding.
  • Long-term receptor regulation is under-described. Receptor binding, activation and regulation were measured over 25 endpoints [2]; how a long-acting agonist behaves at these receptors over extended exposure in native tissue is not resolved by that work.
  • Actions outside glucoregulation and energy metabolism are not covered here. The review cited above reports cardiovascular and bone actions of amylin alongside its major role as a glucoregulatory hormone and an important regulator of energy metabolism [8]; no cagrilintide data on those endpoints is cited above.

Handling

Cagrilintide is supplied as a lyophilized white powder and is stored refrigerated at 2–8 °C. Lipidated peptides of this size are handled like other peptide research materials: the powder is the stable form, reconstituted material is not, and repeated freeze-thaw cycling is the usual avoidable source of degradation. Certificates of analysis report identity, purity and composition for the specific lot assayed and for no other, and one is available on request for the current batch.

This compound is intended for in-vitro research use only. It is not for human, veterinary, diagnostic or therapeutic use, and nothing above should be read as a statement about use in people.