Ipamorelin is a five-residue ghrelin receptor agonist developed in the 1990s and never licensed. Its structure, its selectivity claim and where the evidence stops.
Ipamorelin is a synthetic pentapeptide with the sequence Aib-His-D-2-Nal-D-Phe-Lys-NH2 and a molecular weight of about 712 Da. Three of its five residues are non-natural: aminoisobutyric acid (Aib), D-2-naphthylalanine and D-phenylalanine. Those substitutions were chosen to make the peptide resistant to breakdown and to shape it for one receptor.
It was reported in 1998 by Raun and colleagues at Novo Nordisk in the European Journal of Endocrinology, as one of a series of growth hormone secretagogues built on the earlier GHRP-1 and GHRP-2 peptides. The original abbreviation, NNC 26-0161, still appears in some papers.
Ipamorelin acts at the growth hormone secretagogue receptor, GHS-R1a, which is the receptor for ghrelin. It is therefore a ghrelin mimetic. It does not act at the GHRH receptor, which is the target of sermorelin, tesamorelin and CJC-1295. The two receptor families sit on the same pituitary cells and respond to different signals, which is why ipamorelin is often studied alongside a GHRH-receptor peptide.
| Peptide | Receptor | Family |
|---|---|---|
| Ipamorelin | GHS-R1a (ghrelin receptor) | Secretagogue |
| GHRP-2, GHRP-6, hexarelin | GHS-R1a | Secretagogue |
| Sermorelin, tesamorelin, CJC-1295 | GHRH receptor | Releasing hormone analogue |
The selectivity claim in the 1998 paper is that, in rats and pigs, ipamorelin released growth hormone without the rise in ACTH and cortisol seen with the older GHRPs. That is an animal finding, developer-reported, and it is the main reason the compound is described as "selective" in later literature.
Ipamorelin reached phase 2 clinical trials, run by Helsinn, for postoperative ileus. Development was discontinued and the compound was never licensed for any indication anywhere. There is no marketed ipamorelin product. That matters when reading search results: there is no product information leaflet, no pharmacovigilance record and no regulator-reviewed profile.
| Statement | Evidence tier |
|---|---|
| Binds and activates GHS-R1a | In vitro, demonstrated |
| Releases growth hormone without ACTH or cortisol rise | Animal, developer-reported |
| Any clinical effect | Phase 2 only, discontinued, limited publication |
In our catalogue ipamorelin appears only in the CJC-1295 (no DAC) and ipamorelin blend, and is not listed on its own. A blend certificate has to confirm two identities and report purity against a combined chromatogram, which is set out in CJC-1295 no DAC vs DAC. The three GHRH-receptor peptides are compared in ipamorelin vs CJC-1295 vs sermorelin, and the batch certificates are in the COA library.
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How these names differ, why CJC-1295 DAC data cannot be transferred to a no-DAC listing, and what to check in a blended research material.
Research DocumentationWhat "CJC-1295 no DAC" means, how it differs from the DAC form, and how to check which one a certificate describes.
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