All information below describes the compound's chemical identity, laboratory handling, and the published research literature. It describes molecular targets and results in laboratory and animal models only — not effects in humans — and is not evidence of any human benefit.
What Is Ipamorelin?
Ipamorelin is a synthetic pentapeptide (five amino acid residues, sequence Aib-His-D-2-Nal-D-Phe-Lys-NH2) classified in the published literature as a growth hormone secretagogue. It was first described by Raun and colleagues at Novo Nordisk in the mid-1990s and is structurally derived from the growth-hormone-releasing peptide (GHRP) series. The sequence incorporates several non-natural amino acid residues (including 2-aminoisobutyric acid and D-configured aromatic residues) that confer metabolic stability in laboratory settings.
It does not occur freely in nature; it is a synthetic analogue supplied as a reference compound for in vitro and animal research use only. The sections below summarize its chemical identity, laboratory handling, the molecular targets and model systems examined in the published literature, and the primary references — without describing outcomes, efficacy, or effects in humans.
Research Targets & Pathways
Published preclinical literature has examined Ipamorelin in relation to several molecular systems. These are pathway associations reported in laboratory and animal models; refer to the cited studies for methods and findings.
- Growth hormone secretagogue receptor (GHS-R1a) — examined in relation to receptor binding in pituitary tissue.
- Pituitary GH secretagogue signaling — examined in relation to pulsatile growth hormone release in pituitary cell assays.
- cAMP / calcium second-messenger cascades — studied in relation to downstream signaling in cAMP-accumulation assays.
- Prolactin, ACTH and cortisol axes — examined as off-target endpoints in secretagogue-selectivity characterization.
- Hepatic IGF-1 axis — investigated in relation to IGF-1 gene expression in rodent models.
Model Systems Studied
Ipamorelin has been used as a test compound across a range of published preclinical model systems, primarily in rodents and in vitro cell assays. Refer to the cited literature for study designs, endpoints, and findings.
- In vitro receptor pharmacology — GHS-R1a binding and cAMP-accumulation assays in pituitary tissue.
- Pituitary cell assays — rat pituitary cell growth-hormone-release assay systems.
- Endocrine in vivo — rat and swine models used to characterize GH response alongside prolactin and cortisol endpoints.
- Skeletal — ovariectomized rat and longitudinal bone-growth model systems with bone-turnover marker readouts.
- Body composition — rodent models with IGF-1 and body-composition parameters.
- Gastrointestinal — rodent postoperative-ileus and GI-motility model systems.
Molecular & Technical Profile
C38H49N9O5 | MW 711.85 g/mol | CAS 170851-70-4 | Sequence: Aib-His-D-2-Nal-D-Phe-Lys-NH2
Storage, Reconstitution & Working Concentrations
Storage, reconstitution, and working-concentration values are general laboratory guidance for in vitro and animal research; always confirm against the lot-specific Certificate of Analysis.
Current Research Status
As of the time of this writing, Ipamorelin has not been approved by the U.S. Food and Drug Administration (FDA) for any human therapeutic use. The available evidence base is primarily preclinical, derived from rodent and in vitro models, together with a discontinued gastrointestinal-motility clinical program. Translation to human clinical contexts has not been established through completed controlled clinical trials. Ongoing research continues to characterize the compound's receptor-selectivity and pharmacokinetic profile in experimental systems.
Research FAQ
Is Ipamorelin approved for human use?
No. Ipamorelin has not been approved by the FDA for any human therapeutic use. The evidence base is preclinical (rodent and in vitro models), and the compound is supplied for laboratory research use only — not for human consumption.
What is Ipamorelin's molecular formula and sequence?
A synthetic pentapeptide, sequence Aib-His-D-2-Nal-D-Phe-Lys-NH2 — molecular formula C38H49N9O5, MW 711.85 g/mol, CAS 170851-70-4.
How is Ipamorelin stored and reconstituted?
Store lyophilized at −20°C, protected from light. Reconstitute in sterile water for injection or bacteriostatic water; store the reconstituted solution at 2–8°C for up to ~21 days and avoid repeated freeze–thaw.
What targets and model systems has Ipamorelin been studied in?
Preclinical work has examined the growth hormone secretagogue receptor (GHS-R1a), pituitary GH secretagogue signaling, cAMP/calcium second-messenger cascades, and prolactin/ACTH/cortisol axes as off-target endpoints — across rat pituitary cell GH-release assays, GHS-R1a binding and cAMP-accumulation assays, and rodent in vivo endocrine, bone, body-composition, and GI-motility models.
Selected References
- Raun et al. — Ipamorelin characterized as the first selective GHS with potent GH release and minimal effect on cortisol/prolactin in rat models. European Journal of Endocrinology, 1998.
- Bowers et al. — Structural characterization of synthetic GH-releasing peptides and receptor binding profiles across secretagogue classes. Journal of Clinical Endocrinology & Metabolism, 1998.
- Howard et al. — Identification and characterization of the ghrelin receptor (GHS-R1a) as the molecular target for growth hormone secretagogues. Science, 1996.
- Kojima et al. — Discovery of ghrelin as the endogenous ligand for the GHS receptor, establishing the native signaling axis targeted by ipamorelin. Nature, 1999.
- Svensson et al. — Measured GH pulse amplitude and bone formation markers in rats following ipamorelin administration. Growth Hormone & IGF Research, 1999.
- Muccioli et al. — Quantified GHS-R1a receptor binding affinity and downstream cAMP/calcium signaling cascades in pituitary tissue. European Journal of Pharmacology, 1998.
- Veldhuis et al. — Quantified GH pulse frequency and amplitude in response to secretagogue stimulation using deconvolution analysis in neuroendocrine models. Journal of Clinical Endocrinology & Metabolism, 2008.
- Sigalos et al. — Discussed regulatory status, absence of approved clinical indications, and limitations of translating preclinical GHS data to human populations. Translational Andrology and Urology, 2020.