Ipamorelin
Ipamorelin is a synthetic pentapeptide growth hormone secretagogue that selectively activates the ghrelin/growth hormone secretagogue receptor (GHS-R1a) to stimulate growth hormone release with minimal effect on cortisol, ACTH, or other pituitary hormones, distinguishing it from earlier GHRPs in preclinical studies.
This page is a research-orientation summary, not a dosing guide. For anything beyond general background, read the primary literature or talk to a qualified clinician — specifics like amount, frequency, or administration aren't something we publish here.
What it does & how it works
Ipamorelin binds and activates the growth hormone secretagogue receptor (GHS-R1a), the same G protein-coupled receptor targeted by endogenous ghrelin, on pituitary somatotrophs, triggering phospholipase C activation, increased intracellular calcium, and GH release, an action that synergizes with GHRH-receptor signaling but works through a distinct pathway. Unlike earlier GHRP-family peptides, receptor and hormone-panel studies found that ipamorelin does not meaningfully elevate ACTH, cortisol, prolactin, LH, FSH, or TSH even at high doses, indicating a more receptor-selective pharmacological profile for GH release specifically.
Typical results seen in research
In the original pharmacological characterization in rats, swine, and other preclinical models, ipamorelin produced dose-dependent GH release comparable in potency to other GHRPs such as GHRP-6, while avoiding the concurrent cortisol/ACTH elevations seen with those peptides. Human data on ipamorelin specifically (as distinct from combination GHRH/GHRP protocols) are comparatively sparse in the peer-reviewed literature relative to its widespread research use, so most detailed hormonal selectivity data come from animal and cell-based studies.
How it’s commonly used
Ipamorelin is administered by subcutaneous injection in research settings, often studied alongside a GHRH analog to produce synergistic pulsatile growth hormone release. It has no approved human clinical indication and is used exclusively in investigational contexts.
- European Journal of Endocrinology · 1998 Ipamorelin, the first selective growth hormone secretagogue
- Journal of Clinical Endocrinology & Metabolism · 2001 Do growth hormone-releasing peptides act as ghrelin secretagogues?
Curated from published literature for research orientation. Not an exhaustive review, and not a substitute for reading primary sources.