What Is Ipamorelin? Discovery & Research

What is Ipamorelin?

The Growth Hormone Secretagogue Studied for GH Release & Metabolic Research

Disclaimer: Information provided is for research and educational purposes only. Ipamorelin is not approved by the FDA or any regulatory agency for therapeutic use.

Introduction

Ipamorelin is a synthetic pentapeptide developed as a selective growth-hormone secretagogue (GHS). It binds to the growth-hormone secretagogue receptor (GHS-R1a) in the pituitary to trigger growth-hormone (GH) release while leaving other endocrine pathways—such as ACTH, cortisol, prolactin, and aldosterone—largely unaffected.¹ ² ³.

Known for its high receptor selectivity, predictable pharmacokinetics, and favorable safety profile, Ipamorelin has become a reference compound for studies on GH regulation, metabolism, and tissue repair.⁴ ⁵ ⁶

Ipamorelin Fast Facts

Type: Synthetic pentapeptide growth-hormone secretagogue (GHS)
Sequence: Aib-His-D-2-Nal-D-Phe-Lys-NH₂
Discovered: Late 1990s – Novo Nordisk research team
Mechanism: Selective GHS-R1a agonist that stimulates GH release via ghrelin-like signaling
Key Features: Strong GH stimulation with minimal cortisol or prolactin response ¹ ² ³
Primary Research Areas: Growth hormone release, bone formation, metabolism, tissue repair ⁴ ⁵ ⁶ ⁷ ⁸ ⁹

Chemical Structure

Ipamorelin is a synthetic peptide – designed as a refined analog of earlier GHRPs – developed to isolate ghrelin’s growth hormone release without raising cortisol or prolactin. Its modified amino acids — including Aib and two D-residues — make it more resistant to breakdown and reduce unwanted hormonal effects.

Ipamorelin peptide structure and amino acid sequence

How Ipamorelin Works (in Brief)

Ipamorelin selectively activates GHS-R1a receptors on pituitary somatotroph cells, leading to dose-dependent GH release.¹ ² Unlike earlier secretagogues such as GHRP-6 or Hexarelin, Ipamorelin shows little to no stimulation of cortisol or ACTH, indicating high pathway specificity.³ ⁴ Animal and cell studies suggest downstream effects on bone formation, nitrogen balance, and adipose metabolism distinct from direct GH administration.⁵ ⁶ ⁷

Discovery & Research Milestones

Year	Study & Source	Key Finding
1998	Raun K et al.¹	Ipamorelin discovered as selective GHS with no ACTH or cortisol elevation
1999 2000 2001	Johansen PB et al.² Svensson J et al.⁴ Andersen NB et al.⁵	Studies showing how ipamorelin stimulates bone growth and bone health
1999	Gobburu JVS et al.³	First human PK/PD model; dose-proportional release with short half-life
2001	Lall S et al.⁶	Identified GH-independent adiposity effects of GHSs including ipamorelin.
2009	Aagaard NK et al.⁷	Showed modulation of hepatic nitrogen metabolism and urea synthesis in steroid-treated rats.
2014	Beck DE et al.⁸	Phase-2 clinical trial for postoperative ileus; ipamorelin was safe, with non-significant trend toward faster GI recovery.

Why is Ipamorelin Popular in Research?

Growth Hormone Stimulation: Promotes GH release without elevating other pituitary hormones ¹ ² ³
Bone and Tissue Repair: Improves bone formation and supports healing in animal models ⁴ ⁵ ⁶
Metabolic Regulation: Affects adiposity, insulin sensitivity, and nitrogen turnover ⁶ ⁷ ⁸
Pharmacology & Safety: Short half-life, dose-proportional response, favorable safety data ³ ⁸ ⁹

Summary

Ipamorelin is a selective synthetic GHS that triggers growth-hormone release without altering other hormonal axes. Preclinical and early clinical studies show potential roles in growth regulation, bone metabolism, and recovery research. Its specificity, pharmacokinetic predictability, and safety record make it a cornerstone compound in the study of ghrelin-mimetic peptides.

FAQs About Ipamorelin