Research Overview
Ipamorelin is a synthetic pentapeptide with the published sequence Aib-His-D-2-Nal-D-Phe-Lys-NH2, registered under CAS number 170851-70-4 and with a calculated molecular weight of 711.86 g/mol. Originally described by Raun and colleagues in 1998, it has been characterised across endocrine literature as the first selective growth hormone secretagogue, with action at the ghrelin receptor (GHS-R1a) and minimal reported activity on pathways controlling cortisol, ACTH and prolactin secretion at concentrations active for GH release.
The unusual amino-acid composition, including alpha-aminoisobutyric acid and D-amino-acid residues, has been investigated for conferring resistance to common endopeptidases relative to native ghrelin. This vial contains 5mg of lyophilised peptide powder, released against a 99.2% HPLC purity specification and confirmed by mass spectrometry identity testing, with a batch-specific Certificate of Analysis included with each shipment.
Ipamorelin is supplied for in-vitro and pre-clinical research under appropriate institutional oversight. It is not a medicine, is not approved for human or veterinary use, and the vial is intended for laboratory handling only.
Mechanism Studied in Research
Ipamorelin has been characterised in published literature as a selective agonist of the growth-hormone secretagogue receptor type 1a (GHS-R1a), the endogenous receptor for ghrelin. The receptor is expressed prominently on anterior pituitary somatotrophs and also in hypothalamic nuclei involved in feeding regulation and arousal.
Binding by Ipamorelin engages Gq/11-coupled signalling, activating phospholipase-C beta, generating inositol-1,4,5-trisphosphate, and mobilising calcium from intracellular stores. The rise in cytosolic calcium drives fusion of GH-containing secretory vesicles with the plasma membrane, producing a GH pulse with characteristic onset and decay kinetics.
Concurrent inhibition of potassium channels via PKC-mediated phosphorylation further depolarises somatotrophs and reinforces secretory activity. Unlike unmodified ghrelin or non-selective ghrelin mimetics, Ipamorelin has been characterised in cell-line and animal models as not appreciably activating ACTH-, prolactin-, or aldosterone-related pathways at concentrations effective for GH release.
Research Applications
Pituitary selectivity and safety-pharmacology models. Ipamorelin is described selectively as a frequently referenced compound in studies comparing growth-hormone secretagogues. Researchers use the peptide to define a clean GH-axis signal in cell-line and animal models, free from the confounding cortisol or prolactin elevation observed with less selective ghrelin mimetics.
GH pulse-characterisation studies. Investigators measure serum or supernatant GH at fine time resolution after Ipamorelin exposure to characterise pulse amplitude, duration, and return-to-baseline kinetics, often comparing single-dose and repeated-dose protocols.
Ghrelin-receptor biology and metabolic research. Beyond pituitary somatotrophs, GHS-R1a is expressed in hypothalamic feeding circuits and in peripheral tissues including pancreatic islets. Researchers use Ipamorelin in cell-based and animal models to study selective GHS-R1a activation in feeding, glucose-handling, and energy-balance contexts.
Combination-secretagogue research. Ipamorelin is widely used as the ghrelin-mimetic partner in dual-receptor research designs alongside GHRH analogues such as Sermorelin, CJC-1295, and Tesamorelin. The complementary calcium-driven and cAMP-driven secretory cascades have been investigated for producing larger GH pulses than either compound alone.
Reconstitution Reference
The 5mg vial of Ipamorelin is reconstituted with bacteriostatic water under sterile laboratory conditions. A commonly worked example uses 2ml of bacteriostatic water, producing a final concentration of 2.5mg per ml.
At this concentration, 0.02ml delivers 50mcg and 0.04ml delivers 100mcg on a U-100 research syringe. Researchers add the diluent slowly down the inner glass wall of the vial without directing the stream onto the lyophilised cake, then swirl gently until fully dissolved.
Vials are not shaken. The reconstituted solution should be clear and colourless; any vial showing particulate, cloudiness, or discolouration is discarded. Calculations are confirmed against the institutional research protocol and the vial is labelled with diluent volume, final concentration, and reconstitution date.
Storage and Handling
Lyophilised Ipamorelin vials are stored at -20°C in the original sealed packaging, protected from light and moisture, where the peptide has been characterised in stability literature as remaining intact for extended periods.
Brief ambient transit during shipping does not compromise the lyophilised powder. Once reconstituted with bacteriostatic water, the solution is held at 2-8°C in a laboratory-grade refrigerator and is typically used within 14 to 28 days.
Repeated freeze-thaw cycles of reconstituted material are avoided, which has been associated in literature with aggregation and reduced receptor-binding activity. Vials are kept upright, away from direct sunlight, and labelled with reconstitution date, diluent volume, and final concentration to support institutional documentation and traceability.
References
[2] Smith RG et al. (2001). Beyond the endocrine function: the role of growth hormone secretagogues in the modern management of body composition in hypogonadal males. Translational Andrology and Urology. PMID 32257682
[3] Ghigo E et al. (1998). Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. Pharmacological Research. PMID 9865010
[4] Anderson HC et al. (2000). The growth hormone secretagogue ipamorelin counteracts glucocorticoid-induced loss of cortical bone in rats. Growth Hormone and IGF Research. PMID 11250650