Ipamorelin is a selective growth hormone secretagogue and ghrelin receptor (GHSR-1a) agonist belonging to the GHRP (growth hormone-releasing peptide) family. Unlike recombinant growth hormone, Ipamorelin stimulates the body’s own pulsatile growth hormone secretion through activation of the ghrelin receptor, allowing researchers to investigate physiological GH release rather than direct hormone replacement.

One of the defining characteristics of Ipamorelin is its high receptor selectivity. Compared with earlier growth hormone secretagogues such as GHRP-2 and GHRP-6, published endocrine studies have reported substantially less stimulation of ACTH, cortisol and prolactin, making Ipamorelin one of the most selective compounds within this peptide class.

Why Ipamorelin matters in growth hormone research

Ipamorelin has become an important research peptide because it allows investigators to study growth hormone physiology while producing comparatively limited activation of other pituitary hormone pathways.

Published research has investigated Ipamorelin in relation to:

physiological growth hormone release
IGF-1 regulation
ghrelin receptor signalling
endocrine physiology
body composition
muscle protein metabolism
recovery physiology
ageing-related endocrine changes

Unlike many earlier GHRPs, Ipamorelin is primarily valued for its selectivity rather than the absolute magnitude of GH release, making it an important comparator in endocrine research.

How Ipamorelin works

Ipamorelin binds selectively to the growth hormone secretagogue receptor (GHSR-1a), also known as the ghrelin receptor. Activation of this receptor stimulates pulsatile secretion of endogenous growth hormone from the anterior pituitary. Unlike direct GH administration, this mechanism preserves the body’s own endocrine regulation and feedback systems, making Ipamorelin useful for investigating physiological growth hormone dynamics rather than pharmacological hormone replacement.

Published endocrine studies have consistently highlighted another distinguishing characteristic: minimal stimulation of ACTH, cortisol and prolactin compared with earlier GHRPs.

What makes Ipamorelin different from other GH secretagogues?

Ipamorelin

selective ghrelin receptor agonist
highly selective GH release
minimal ACTH stimulation
minimal cortisol response
minimal prolactin response

GHRP-2

stronger overall GH release
broader pituitary stimulation
more endocrine cross-activation

GHRP-6

stimulates GH release
often associated with marked appetite stimulation
broader hormonal profile

CJC-1295

GHRH analogue
stimulates GH through a different receptor pathway
frequently investigated alongside Ipamorelin because the mechanisms complement one another

Human clinical and endocrine research

Unlike GLP-1 receptor agonists, Ipamorelin has not been investigated through large cardiovascular or obesity outcome programmes. Instead, published human studies have focused primarily on endocrine physiology, receptor pharmacology and growth hormone secretion.

Clinical investigations have demonstrated that Ipamorelin produces dose-dependent increases in endogenous growth hormone release while exhibiting substantially greater endocrine selectivity than earlier growth hormone secretagogues. In multiple human studies, little or no clinically relevant stimulation of cortisol, ACTH or prolactin was observed, distinguishing Ipamorelin from several first-generation GHRPs.

Although Ipamorelin was later investigated for postoperative ileus, that programme did not demonstrate sufficient efficacy for further pharmaceutical development. Its scientific value today lies primarily in endocrine and growth hormone research rather than as an approved therapeutic agent.

Published safety observations

Published human studies generally describe Ipamorelin as being well tolerated during clinical investigation. Reported adverse events have typically been mild, with the overall safety profile reflecting its relatively selective receptor activity.

From an endocrine perspective, one of the most important observations has been the limited stimulation of cortisol, ACTH and prolactin compared with several earlier growth hormone secretagogues. This endocrine selectivity remains one of the defining characteristics of Ipamorelin in the published literature.

Research protocols reported in the literature

Published clinical studies have investigated Ipamorelin using multiple dosing strategies depending on study objectives, including endocrine physiology, postoperative recovery and pharmacodynamic evaluation.

Rather than supporting a single standard protocol, the published literature reflects a range of experimental designs intended to characterise growth hormone secretion, receptor selectivity and endocrine responses under controlled conditions.

The dosing schedules reported in published studies are summaries of research methodology and are not instructions for use of this product.

Key published studies

Raun K et al. Ipamorelin, the First Selective Growth Hormone Secretagogue. European Journal of Endocrinology. 1998.

The landmark paper introducing Ipamorelin and demonstrating its highly selective stimulation of growth hormone release with minimal effects on ACTH, cortisol and prolactin.

Svensson J et al. Pharmacokinetic–pharmacodynamic modelling of Ipamorelin in healthy volunteers. Pharmaceutical Research. 1999.

A foundational human study describing dose-response relationships, growth hormone release and pharmacodynamic characteristics.

Bowers CY. Growth Hormone Secretagogues.

A comprehensive review covering the physiology of ghrelin receptor agonists, receptor biology and the role of peptides such as Ipamorelin within the broader GH secretagogue family.

Ghigo E et al. Growth Hormone Secretagogues: Clinical Pharmacology and Endocrine Physiology.

An overview of endocrine mechanisms, receptor pharmacology and clinical development across the GH secretagogue class.

FAQ

What is Ipamorelin?

Ipamorelin is a selective growth hormone secretagogue that activates the ghrelin receptor (GHSR-1a) to stimulate physiological release of endogenous growth hormone. Unlike recombinant GH, it promotes the body’s own pulsatile GH secretion through pituitary signalling.

How does Ipamorelin differ from GHRP-2 and GHRP-6?

Ipamorelin is considered the most selective member of the classic GHRP family. Published endocrine studies have shown minimal stimulation of ACTH, cortisol and prolactin compared with earlier growth hormone secretagogues, making it particularly valuable for research focused on selective GH release.

Why is Ipamorelin frequently combined with CJC-1295?

Although both peptides influence growth hormone secretion, they act through different receptor systems. CJC-1295 is a GHRH analogue, while Ipamorelin activates the ghrelin receptor. Researchers have investigated this complementary receptor activation to better understand physiological GH pulsatility and endocrine signalling.

What research areas commonly investigate Ipamorelin?

Published research has explored Ipamorelin in endocrine physiology, growth hormone regulation, IGF-1 signalling, body composition, muscle metabolism, ageing-related endocrine changes and ghrelin receptor biology. Its receptor selectivity makes it one of the most widely studied peptides within the GH secretagogue class.

Is Ipamorelin intended for human use?

No. Ipamorelin supplied by LIFE Peptide is provided strictly for laboratory and analytical research. It is not intended for human consumption, diagnosis, treatment or prevention of disease. Any discussion of published studies on this page summarises the scientific literature relating to the Ipamorelin molecule rather than the intended use of this product.

Product characteristics

Application: laboratory and analytical research
Use restriction: not for human consumption; not for medical, veterinary or cosmetic use
Produced in GMP-compliant facilities under strict QC protocols.
Each batch carefully lab tested after production (you can find Certificate of Analysis under product pictures).
Freeze-dried (lyophilized) for maximum stability and extended shelf life.
Sealed in sterile vials, ready for reconstitution.
Purity: ≥ 99.90% , HPLC tested, independently confirmed high purity and identity consistency. View third-party verification.
Appearance: white lyophilized powder
Molecular formula: C₄₀H₅₂N₁₀O₆
Molecular weight: 768.93
Peptide backbone formula shown. Counterion (acetate/TFA) content quantified in batch-specific COA.
Sequence: Gly-Aib-His-D-2-Nal-D-Phe-Lys-NH2
Storage: unopened lyophilized vials are best stored refrigerated at 2–8°C, which is the storage method confirmed by our manufacturing partner and suitable for up to 24 months. Refrigeration is preferred because it minimizes unnecessary freeze–thaw cycles during routine handling. If substantially longer-term storage is required, unopened lyophilized vials may also be kept frozen. Once reconstituted, always store at 2–8°C and do not freeze.

Reconstitution and handling

Ipamorelin is supplied as a lyophilised vial and should be handled using standard peptide reconstitution procedures appropriate to the research setting. Must be reconstituted with bacteriostatic water before use. To help preserve structural integrity, add the chosen solvent slowly against the inside wall of the vial rather than directly onto the peptide cake, and avoid vigorous shaking. Gentle swirling is generally sufficient once the peptide has fully dissolved. Standard laboratory practice also includes allowing refrigerated vials to reach room temperature before reconstitution to minimise condensation inside the vial.

For other solvent selection, concentration planning and storage guidance, see the full Peptide Reconstitution Guide and Reconstitution Calculator.

Selected research references

Raun K et al. “Ipamorelin, the first selective growth hormone secretagogue.” European Journal of Endocrinology, 1998.
Smith RG et al. “Growth hormone secretagogues: physiology and clinical relevance.” Trends in Endocrinology & Metabolism, 2005.
Bowers CY. “GH releasing peptides — structure and kinetics.” Journal of Pediatric Endocrinology and Metabolism, 1993.
Hansen BS et al. “Ipamorelin, a new potent growth hormone-releasing peptide.” American Journal of Physiology, 1999.

Related research context

Ipamorelin belongs to the growth hormone secretagogue research class, which includes compounds investigated for endocrine signaling and GH-axis modulation.
For a broader overview of GH signaling pathways and comparative peptide mechanisms, see our Growth hormone peptides research guide.
Researchers studying GH pathway interaction may also examine:
CJC-1295 (GHRH analogue research peptide)
GHRP-2
GHRP-6
Browse all compounds in the Growth hormone secretagogues category.
Researchers investigating endocrine regulation may also explore compounds in the Metabolic research category, including GLP-1 and multi-pathway incretin agonists.

NOTE: This is for educational reference only and does not constitute medical advice.

Disclaimer
This product is sold for research purposes only. It is not intended to diagnose, treat, cure, or prevent any disease. Buyer assumes full responsibility for proper handling and use.

growth hormone peptide

Ipamorelin 5 mg