Ipamorelin is a research peptide studied for its role in performance & hormone research. This page covers its mechanism of action, published research, preclinical protocols, and analytical specifications for researchers.
Quick Reference: Ipamorelin
CAS Number
170851-70-4
Molecular Formula
C38H49N9O5
Molecular Weight
711.9 g/mol
Sequence / Form
Aib-His-D-2-Nal-D-Phe-Lys-NH2
Physical Form
Lyophilized powder
Purity (QSC)
≥99% (HPLC verified)
Storage
-20°C (lyophilized); 4°C after reconstitution, use within 28 days
Reconstitution
Add 2ml bacteriostatic water per 10mg vial. Inject slowly along vial wall, swirl gently.
Mechanism of Action
Ipamorelin is a synthetic pentapeptide and selective growth hormone secretagogue receptor (GHSR-1a) agonist — often described as the most selective GH secretagogue characterised at its time of development. Its selectivity for the GHS receptor over other pituitary receptors is the key feature that has made it a research reference compound in the GH secretagogue field.
GHSR-1a Agonism: Ipamorelin binds to and activates the growth hormone secretagogue receptor (also known as the ghrelin receptor), triggering GH release from somatotroph cells in the anterior pituitary. This activation is dependent on the presence of GHRH signalling — ipamorelin amplifies rather than independently drives pulsatile GH release.
Selectivity Profile: What distinguished ipamorelin from earlier GH secretagogues (GHRP-2, GHRP-6, hexarelin) in research was its minimal effect on cortisol, prolactin, and ACTH secretion at doses that effectively stimulate GH. Studies have documented that ipamorelin produces dose-dependent GH release without the cortisol and prolactin co-stimulation seen with GHRP-2 and GHRP-6, making it a cleaner research tool for isolated GH axis study.
Pulsatility Preservation: Unlike GHRH analogues such as CJC-1295 with DAC, which produce sustained GH elevation, ipamorelin stimulates GH release in a pulsatile pattern that more closely mimics endogenous GH secretion dynamics — a research-relevant distinction for studies examining physiological GH axis regulation.
Research Applications
GH Axis Research: Ipamorelin’s selectivity has made it a standard reference compound for studying isolated GH secretagogue receptor activation and comparing the relative contributions of GHSR agonism vs GHRH signalling to GH release.
IGF-1 Axis Studies: Research examining the downstream effects of GH secretagogue-induced GH release on IGF-1 production, IGF-binding proteins, and anabolic signalling pathways.
Combination Research (GHRH + GHSR): Ipamorelin is frequently studied in combination with GHRH analogues (particularly CJC-1295 No DAC) to examine the synergistic effects of dual-pathway GH axis stimulation on GH pulse amplitude, frequency, and downstream hormonal responses.
Bone and Body Composition Research: Preclinical studies have examined the effects of sustained GH secretagogue administration on bone mineral density, lean mass, and fat mass markers in rodent models.
GI Motility Research: GHS receptors are expressed throughout the gastrointestinal tract, and ipamorelin has been studied in GI motility models — including postoperative ileus models — given its selectivity allowing GI effects to be isolated from broader hormonal responses.
Key Published Research
The following publications represent primary research relevant to Ipamorelin. Full citations are available via PubMed. QSC does not endorse or make claims based on this research.
Raun et al. (1998)
“Ipamorelin, the First Selective Growth Hormone Secretagogue” — European Journal of Endocrinology
Original characterisation paper defining ipamorelin’s selectivity profile — demonstrating equivalent GH release to GHRP-6 with absent cortisol/prolactin co-stimulation.
Svensson et al. (2000)
“Two-Month Treatment of Obese Subjects with the Oral Growth Hormone Secretagogue MK-677 Increases GH Secretion, Fat-Free Mass, and Energy Expenditure” — Journal of Clinical Endocrinology & Metabolism
While studying a different secretagogue, establishes the research methodology for GH secretagogue axis studies relevant to ipamorelin research.
Nass et al. (2008)
“Effects of an Oral Ghrelin Mimetic on Body Composition and Clinical Outcomes in Healthy Older Adults” — Annals of Internal Medicine
Demonstrates the research methodology applied to selective GHSR agonists in body composition and GH axis studies in aging models.
Research Protocol Reference
Parameters below reflect those used in published preclinical research. Provided for informational context only.
Model / Context
Dose Range
Route
Protocol Notes
Rodent GH Axis Model
100–300 μg/kg
Subcutaneous injection
Typically acute single-dose for GH pulse studies; chronic protocols 2–4 weeks for body composition endpoints
In Vitro Pituitary Cell
0.1–100 nM
Added to pituitary cell culture
Used for receptor binding, cAMP signaling, and GH secretion studies in somatotroph cell lines
Combination with CJC-1295
200 μg/kg ipamorelin + 200 μg/kg CJC (No DAC)
Subcutaneous injection
Common dual-pathway protocol in published rodent GH research
Frequently Asked Questions
What is ipamorelin?
Ipamorelin is a synthetic pentapeptide and selective ghrelin receptor (GHSR-1a) agonist that stimulates pulsatile growth hormone release from the anterior pituitary. It is distinguished in research by its selectivity — producing GH release without significant co-stimulation of cortisol, prolactin, or ACTH.
Is ipamorelin a GHRH?
No. Ipamorelin is a growth hormone secretagogue receptor (GHSR) agonist — it acts through the ghrelin receptor, not the GHRH receptor. GHRH analogues (like CJC-1295, sermorelin) act through a distinct receptor. Ipamorelin and GHRH analogues are often studied in combination because they work through complementary pathways.
What is the difference between ipamorelin and GHRP-6?
Both are GHSR agonists, but ipamorelin’s defining research characteristic is its selectivity — it produces comparable GH release to GHRP-6 without GHRP-6’s significant cortisol and prolactin co-stimulation. This makes ipamorelin a cleaner research tool when isolated GH axis effects are the study endpoint.
How is ipamorelin typically studied in combination?
Ipamorelin is most commonly studied in combination with CJC-1295 (No DAC), a GHRH analogue. The rationale is dual-pathway stimulation: CJC-1295 activates the GHRH receptor while ipamorelin activates the ghrelin receptor, producing synergistically amplified GH pulses compared to either alone.
What purity is QSC ipamorelin?
QSC ipamorelin is verified at ≥99% purity by HPLC and mass spectrometry. COA available on the product page and via the Janoshik testing portal.
Research Use Only: All products sold on qsc-usa.com are intended strictly for laboratory research purposes only. They are not approved for human consumption, veterinary use, or any other application. Researchers are responsible for understanding and complying with local regulations governing research chemicals in their jurisdiction.
