Growth-hormone secretagogue (ghrelin/GHS-R agonist)

Ipamorelin

The first highly selective GH secretagogue.

Foundational only

At a glance

Sequence
Aib-His-D-2-Nal-D-Phe-Lys-NH2 (pentapeptide)
Molecular weight
CAS
Class
Growth-hormone secretagogue (ghrelin/GHS-R agonist)
Aliases

Overview

Selective ghrelin-receptor agonist that stimulates growth-hormone release with minimal effect on cortisol, prolactin or ACTH — the cleanest hormonal profile among GH secretagogues.

Recent standalone primary research is scarce.

Mechanism

Binds GHS-R1a on pituitary somatotrophs to trigger pulsatile GH release.

Research

What the studies show

Defining pharmacology of ipamorelin

Raun K, et al. · European Journal of Endocrinology · 1998 · Foundational

The defining pharmacology paper; characterises ipamorelin's potency and its surprising lack of ACTH/cortisol release even at high doses.

Ipamorelin counteracts glucocorticoid-induced bone loss

Andersen NB, et al. · Rat model · — · Preclinical

Ipamorelin counteracts glucocorticoid-induced loss of bone formation, supporting anti-catabolic effects.

Bone mineral content with GH-secretagogue dosing

Johansen PB, et al. · DXA rat studies · — · Preclinical

Demonstrates increased bone mineral content with GH-secretagogue dosing in vivo.

PK/PD modelling of GH release

Gobburu JV, et al. · PK/PD modelling · — · Foundational

Models the GH-release kinetics that underpin dosing rationale.

GH-secretagogue peptide review

Various · Narrative review · 2026 · Review

Places ipamorelin within an evidence-tier framework alongside CJC-1295, noting the absence of new human trials.

Evidence summary

Exceptionally well-characterised pharmacology, prized as the most selective growth-hormone secretagogue with a notably clean hormonal profile. A mature, well-understood research tool with a solid foundation for continued study.