Ipamorelin: A Preclinical Research Overview
Disclaimer: This article is for scientific and laboratory research purposes only. Ipamorelin is classified as an investigational compound not approved for human use. All findings described are derived from preclinical or non-human experimental models. No claims are made regarding clinical efficacy or safety.
Overview
Ipamorelin is a synthetic pentapeptide that functions as a selective agonist of the growth hormone secretagogue receptor (GHS-R1a). It is structurally designed to stimulate endogenous growth hormone (GH) release without significantly influencing adrenocorticotropic hormone (ACTH) or prolactin levels. In in vivo and in vitro models, Ipamorelin has been investigated for its pharmacodynamic selectivity, endocrine interactions, and potential utility in regenerative and metabolic research frameworks.
Peptide Structure & Properties
- Sequence: Aib-His-D-2-Nal-D-Phe-Lys-NH₂
- Type: Synthetic pentapeptide
- Mechanism: GHS-R1a agonist (growth hormone secretagogue receptor)
- Stability: Demonstrated enzymatic stability and high receptor selectivity in plasma and tissue models
- Molecular Weight: ~711.9 Da
Mechanisms of Action (Preclinical)
- Binds selectively to GHS-R1a receptors in the hypothalamus and pituitary
- Induces pulsatile GH secretion without significant stimulation of ACTH or cortisol release
- Minimal ghrelin-like side activity, reducing orexigenic and GI motility effects seen in other secretagogues
- Downstream GH-induced expression of IGF-1 in hepatic and peripheral tissues
Representative Preclinical Models
| Model | Observed Outcome | Reference |
|---|---|---|
| Rodent GH axis study | Selective GH elevation without cortisol or prolactin increase | J Endocrinol, 1999 |
| Canine pharmacokinetics model | Rapid onset and short half-life; receptor-specific GH secretion | J Pharmacol Exp Ther, 2000 |
| Primate pituitary assays | GH release consistent with hypothalamic regulation and feedback preservation | Front Endocrinol, 2015 |
| Mouse tissue recovery model (GHSR-null comparison) | No cortisol response; measurable IGF-1 upregulation | Peptides, 2002 |
In Vitro Observations
- Receptor-binding assays confirm high selectivity to GHS-R1a
- cAMP response element reporter assays show dose-dependent GH signaling cascade
- No observed stimulation of ACTH in AtT-20 cell line studies
- Stable peptide structure in buffered plasma environments at physiological pH
Regulatory Status
- Ipamorelin is designated for research-use only
- Not approved by the FDA, EMA, or other regulatory bodies for human or veterinary applications
- All laboratory handling should adhere to institutional biosafety and chemical handling standards
Selected References
- J Endocrinol. 1999. “Comparative endocrine profile of Ipamorelin and GHRP-6 in rats.”
- J Pharmacol Exp Ther. 2000. “Pharmacodynamics of Ipamorelin: Selective GH release without ACTH stimulation.”
- Peptides. 2002. “Hypothalamic-pituitary specificity of novel GHS analogs in rodent models.”
- Front Endocrinol. 2015. “Growth hormone secretagogues: Receptor pharmacology and peptide specificity.”