Ipamorelin
Molecular Research Profile · Target purity > 99.0% · Half-life ~2 hours
Highly selective ghrelin receptor (GHS-R1a) agonist. Releases growth hormone without the appetite stimulation, cortisol elevation, or prolactin spikes common with earlier GHRPs like GHRP-6.
Mechanism of Action
Ipamorelin is a pentapeptide (Aib-His-D-2-Nal-D-Phe-Lys-NH2) ghrelin-mimetic with high selectivity for the growth hormone secretagogue receptor 1a (GHS-R1a). Unlike first-generation GHRPs (GHRP-6, GHRP-2), ipamorelin has minimal off-target activity at the motilin receptor and no interaction with the H1 histamine receptor, resulting in a far cleaner pharmacological profile with virtually no appetite stimulation, gastric motility effects, or histaminergic side effects.
At the somatotroph level, ipamorelin activates GHS-R1a signaling via Gαq/11 → phospholipase C → IP3-mediated calcium release, triggering exocytosis of pre-synthesized GH vesicles. It also antagonizes somatostatin tone at the pituitary level, effectively reducing the inhibitory brake on GH release. The GH pulse amplitude produced by ipamorelin is dose-dependent up to approximately 1 mcg/kg, above which additional dosing primarily extends pulse duration rather than peak amplitude.
Co-administered with CJC-1295 no DAC (GHRH analog), ipamorelin's effect is amplified 2–5×: the GHRH analog increases the GH "pool available for release" while ipamorelin triggers the release signal. This is the biochemical basis for the widely-used CJC/Ipamorelin combination protocol.
Research History & Context
Ipamorelin was developed in the late 1990s by Novo Nordisk as part of a broader GHS-R1a agonist program aimed at identifying growth hormone secretagogues with improved selectivity profiles over earlier compounds. The goal was to find a peptide that stimulated GH release without the side-effect burden of GHRP-6 (appetite, cortisol, prolactin) while maintaining efficacy.
Preclinical studies in rats and swine demonstrated dose-dependent GH release with a potency comparable to GHRP-6 but without measurable effects on ACTH/cortisol, prolactin, or food intake. Human Phase 1 data confirmed the selectivity profile. While ipamorelin was never commercialized as a therapeutic, it has become a standard research tool in growth hormone axis studies and one of the most widely studied GHS-R1a agonists in the independent biohacking research community.
Storage & Handling
Store lyophilized ipamorelin at -20°C, protected from light and moisture. Stability exceeds 24 months under these conditions. The pentapeptide structure is moderately stable; the Aib (α-aminoisobutyric acid) residue at position 1 provides resistance to aminopeptidase degradation.
Reconstituted ipamorelin should be stored at 2–8°C and used within 21 days. Do not freeze reconstituted solutions — repeated freeze-thaw cycles reduce bioactivity. Ipamorelin is compatible with CJC-1295 no DAC in the same syringe for combined research protocols; no interaction or aggregation has been reported at standard concentrations.
Reconstitution & Research Dosing
For Ipamorelin, the standard laboratory reconstitution is 2.0 ml BAC water for 2mg / 5mg vial. A typical research study window uses 100 - 300 mcg / 1-3× daily.
For a 2mg ipamorelin vial, add 2.0 ml BAC water (100 mcg per 0.1 ml / 10 IU). For a 5mg vial, add 2.5 ml BAC water (200 mcg per 0.1 ml). In the standard CJC/Ipamorelin research protocol, both peptides are often reconstituted at complementary concentrations and drawn into the same syringe immediately before administration.
Use the Reconstitution Calculator for exact syringe units →Explore Related Research Compounds
Research Use Only (RUO): Ipamorelin is discussed strictly as an in-vitro laboratory research compound. Nothing on this page constitutes human or clinical administration guidance. Always verify purity through independent third-party HPLC/MS analysis before use.