Ipamorelin is one of the most requested growth hormone secretagogues in UK research supply, and one of the better characterised. It was first described by Raun and colleagues in 1998 as a selective agonist at the ghrelin receptor, and most of what is known about it comes from that original pharmacology work and the animal studies that followed. This guide covers the molecule, the receptor it acts on, how it compares with the other secretagogues in our range, and how to handle it.
The molecule
| Type | Synthetic pentapeptide (five amino acids) |
| Sequence | Aib-His-D-2-Nal-D-Phe-Lys-NH2 |
| Molecular formula | C38H49N9O5 |
| Molecular weight | 711.9 g/mol |
| CAS number | 170851-70-4 |
| Class | Growth hormone secretagogue (GHS); ghrelin receptor (GHS-R1a) agonist |
The sequence uses non-natural residues (Aib, D-2-Nal, D-Phe), which is what gives it resistance to enzymatic breakdown compared with a native peptide of the same length.
Receptor pharmacology
Ipamorelin binds the growth hormone secretagogue receptor type 1a – the same receptor as the endogenous hormone ghrelin. In the original in vitro and rat pituitary work it was notable for being selective: it stimulated growth hormone release from pituitary cells without the accompanying rise in ACTH, cortisol or prolactin seen with earlier secretagogues such as GHRP-6 and GHRP-2. That selectivity is the main reason it became a standard reference compound in GHS research.
How it differs from the other secretagogues we stock
- Ipamorelin vs CJC-1295: different receptors entirely. Ipamorelin is a ghrelin-receptor agonist; CJC-1295 is a GHRH analogue acting at the GHRH receptor. Because they act on two separate pathways they are frequently studied together, and we supply a pre-blended CJC-1295 + Ipamorelin vial for that reason.
- Ipamorelin vs Tesamorelin: again a GHRH-receptor analogue rather than a ghrelin-receptor agonist; tesamorelin is the 44-residue GHRH backbone with a stabilising N-terminal modification.
- Ipamorelin vs GHRP-6 / GHRP-2: same receptor, but the older GHRPs show measurable effects on cortisol and prolactin in animal models; ipamorelin does not.
What the published research covers
- Pituitary somatotroph signalling and GH pulse characterisation in rat and pig models
- Receptor selectivity studies against ACTH, cortisol and prolactin endpoints
- Postoperative ileus and gastric-emptying models in rats
- Bone formation and mineral-density models in rodents
Ipamorelin was investigated clinically for postoperative ileus but development was discontinued; it is not an approved medicine in any jurisdiction. Everything above is preclinical.
Handling and storage
- Supplied lyophilised in a 10mg vial. Store at 2–8°C, protected from light.
- Reconstitution solvent, volume and solution storage are determined by the laboratory's own method; see our storage and stability guide for the general chemistry.
- Batch-specific HPLC and mass spectrometry certificates available on request.
View Ipamorelin 10mg or browse the full research peptide range.
All products referenced are supplied for in vitro and laboratory research only and are not for human or veterinary use. Peptide Stock is operated by UK Research Group Ltd.
