Cagrilintide is an amylin analogue, not a GLP-1
Cagrilintide descends from the pancreatic hormone amylin, not from GLP-1. What the molecule is, how it was engineered, why it is paired with semaglutide in trials, and its status as of September 21, 2026.
Cagrilintide is a synthetic analogue of amylin, a 37-residue hormone made in the pancreas, not of GLP-1. It descends from a different parent hormone, carries a different sequence and binds amylin and calcitonin receptors rather than the GLP-1 receptor. The mix-up comes from its partner: in clinical development it is co-formulated with semaglutide, and research catalogs shelve the two together. It has no US approval and is investigational.
What amylin is
Amylin, also called islet amyloid polypeptide (IAPP), is a 37-residue peptide hormone. The UniProt entry for human IAPP (P10997) gives the mature hormone as residues 34 to 70 of an 89-residue precursor, with a disulfide bond between the cysteines at positions 2 and 7 of the mature chain and an amidated C-terminal tyrosine. Its one-letter sequence is KCNTATCATQRLANFLVHSSNNFGAILSSTNVGSNTY.
Human amylin has, in the words of the Novo Nordisk chemists who developed cagrilintide, "a high propensity toward the formation of amyloid fibrils," which made the native hormone a poor starting point for a long-acting molecule.
From amylin to pramlintide to cagrilintide
The first amylin analogue to reach the market was pramlintide. PubChem's systematic name for it is "Amylin (human), 25-L-proline-28-L-proline-29-L-proline-": human amylin with three prolines swapped in, the residues found at those positions in rat amylin, which does not form fibrils.
Cagrilintide keeps those three prolines and adds more. Aligning the CAS-style index name PubChem lists for CID 171397054 against the mature human sequence gives six substitutions and two additions:
| Position | Human amylin | Cagrilintide | Purpose described in the literature |
|---|---|---|---|
| 14 | Asn (N) | Glu (E) | forms a salt bridge with position 17 to stabilise the N-terminal helix |
| 17 | Val (V) | Arg (R) | the other half of that salt bridge |
| 25 | Ala (A) | Pro (P) | rat-amylin residue, carried over from pramlintide |
| 28 | Ser (S) | Pro (P) | rat-amylin residue, carried over from pramlintide |
| 29 | Ser (S) | Pro (P) | rat-amylin residue, carried over from pramlintide |
| 37 | Tyr (Y) | Pro (P) | C-terminal proline, described as enhancing activity at both calcitonin and amylin receptors |
| N-terminus | free amine | C20 fatty diacid via a gamma-glutamyl spacer | albumin binding (Kruse et al., 2021) |
| C-terminus | amide | amide (prolinamide) | retained from the parent hormone |
The Cys2 to Cys7 disulfide is retained; the index name ends "cyclic (3→8)-disulfide" because its numbering counts the gamma-glutamyl spacer as residue 1. The lipid is a 20-carbon diacid (PubChem names the acyl group "19-carboxy-1-oxononadecyl"), the same design idea as the fatty diacid on semaglutide described in Thirty-nine residues and a fatty acid, applied at the N-terminus instead of a lysine side chain.
The identity block, from PubChem: formula C194H312N54O59S2, average molecular weight 4409, CAS 1415456-99-3, INN cagrilintide, Novo Nordisk code NN0174-0833. The development chemistry is in Kruse et al., "Development of Cagrilintide, a Long-Acting Amylin Analogue," Journal of Medicinal Chemistry, 2021, where cagrilintide is compound 23. How to read a peptide sequence explains the notation used above.
Why it is not a GLP-1
Three facts keep cagrilintide out of the GLP-1 class.
Different parent. GLP-1 analogues such as semaglutide are built from glucagon-like peptide-1, a gut hormone. Cagrilintide is built from amylin, a pancreatic hormone encoded by the IAPP gene.
Different receptors. GLP-1 analogues act at the GLP-1 receptor. A 2025 structural paper in Nature Communications describes cagrilintide as "a long-acting amylin and calcitonin receptor agonist" and reports structures of it bound to the three amylin receptors (AMY1R, AMY2R, AMY3R) and to the calcitonin receptor (CTR). None of these is the GLP-1 receptor.
Different chemistry. The disulfide loop at the N-terminus, the C-terminal amide and the proline-rich tail are amylin features. GLP-1 analogues have none of them.
The two classes share engineering: a fatty diacid attached through a spacer so the molecule rides on albumin, and a size of around 4 kDa. Add the co-formulation with a GLP-1 analogue and a place on the GLP-1 and metabolic shelf of most research catalogs, and the molecules look like siblings when they are not.
None of that changes what a certificate should show. The mass spectrum should match 4409, not the 4114 of semaglutide, and an HPLC identity run should not co-elute with any GLP-1 analogue.
The CagriSema program
Novo Nordisk is developing a co-formulation of cagrilintide and semaglutide under the name CagriSema. It is in Phase 3 programs sponsored by Novo Nordisk (REDEFINE and REIMAGINE). ClinicalTrials.gov listed 44 studies with cagrilintide as an intervention when queried on September 21, 2026, all sponsored by Novo Nordisk A/S, and most of them CagriSema studies.
The pairing is a fact about Novo's program, not a property of the molecule. Cagrilintide is also being studied on its own (for example NCT07220642 and NCT07220759, both Phase 3). This site does not describe what either molecule does in people and does not publish combination or use guidance.
Status as of September 21, 2026
Cagrilintide has no US approval. It is investigational, sponsored by Novo Nordisk A/S, in Phase 3 (the CagriSema studies NCT06131437 and NCT06323174 are completed; NCT07564414 is recruiting). Novo Nordisk announced on December 18, 2025 that it had submitted a New Drug Application to FDA for CagriSema; no FDA decision on that application had been published on fda.gov when this piece was written. Cagrilintide is named in the CBP Cincinnati release of March 31, 2026 among peptides seized as unapproved. It is not on any FDA 503A category list and is not named in WADA's 2026 Prohibited List.
A research-grade cagrilintide vial is a lyophilized reagent labeled research use only, not CagriSema; Retatrutide is investigational makes the same point for retatrutide.
Sources
- Cagrilintide, PubChem CID 171397054, National Library of Medicine, accessed 2026-09-21
- Kruse T et al., Development of Cagrilintide, a Long-Acting Amylin Analogue, Journal of Medicinal Chemistry 64(15):11183–11194, 2021 (PubMed record)
- Islet amyloid polypeptide, human, UniProt P10997, accessed 2026-09-21
- Pramlintide, PubChem CID 70691388, National Library of Medicine, accessed 2026-09-21
- Cao J et al., Structural and dynamic features of cagrilintide binding to calcitonin and amylin receptors, Nature Communications, 2025
- Novo Nordisk files for FDA approval of CagriSema, Novo Nordisk press release, December 18, 2025
- Novo Nordisk company announcement on the REIMAGINE 2 trial, Novo Nordisk, February 2, 2026
- Studies with cagrilintide as an intervention, ClinicalTrials.gov API v2, queried 2026-09-21
- Cincinnati CBP foils scheme to smuggle over 5,000 unapproved peptides into the U.S., U.S. Customs and Border Protection, March 31, 2026
- Bulk Drug Substances Nominated for Use in Compounding Under Section 503A, FDA, updated May 14, 2026
- The 2026 Prohibited List, World Anti-Doping Agency, effective January 1, 2026
For laboratory research use only. Not a drug, not a supplement, and nothing here is a claim about what any of this material does in a person or an animal.