Molecular data
| Molecular formula | C38H49N9O5 |
|---|---|
| Molecular weight | 711.85 Da |
| Sequence | Aib-His-D-2-Nal-D-Phe-Lys-NH₂ |
| Sequence length | 5 residues |
| CAS / identifier | 170851-70-4 |
| Physical form | Lyophilized Powder |
| Available sizes | 10mg |
How it works
Ghrelin Receptor Activation
Ipamorelin selectively binds Growth Hormone Secretagogue Receptor 1a (GHSR-1a) on anterior pituitary somatotrophs, with GH release measured in a concentration-dependent manner. It acts via the same receptor as ghrelin but with greater selectivity and without the appetite-related off-target activity.
- Selective GHSR-1a (ghrelin receptor) agonism
- Dose-dependent GH release (rat ED50: 80 nmol/kg)
- No desensitization across repeated preclinical exposures
No Cortisol or Prolactin Elevation
Unlike GHRP-2 and GHRP-6, ipamorelin does not raise ACTH, cortisol or prolactin at concentrations that produce substantial GH release. This was characterised in escalation studies and marks ipamorelin as the first pentapeptide GH secretagogue with this selectivity profile.
- No ACTH or cortisol elevation (unlike GHRP-6)
- No significant prolactin elevation
- Clean pituitary selectivity
Physiologic GH Secretion Pattern
GH release is measured in discrete, pulsatile bursts resembling endogenous GH secretion physiology. That pattern differs from continuous GH elevation and is maintained across repeated exposures.
- Preserves pulsatile GH secretion pattern
- Peak GH response at approximately 40 minutes
- Additive effect when combined with GHRH analogs
What the research shows
Selective GH Secretagogue
First pentapeptide GH secretagogue characterised with GH release but no accompanying cortisol, ACTH or prolactin rise — the selectivity benchmark for GHS research.
GH Secretion & Sleep
In human study populations, GH was measured during early nocturnal sleep phases following ipamorelin, with no accompanying cortisol change — a model for GH secretion across sleep-wake cycles.
Bone Growth Models
Dose-dependent bone growth observed in rat models: 52 vs 42 µm/day at effective doses, confirming GH-mediated downstream effects on skeletal tissue in preclinical studies.
Synergy with GHRH Analogs
Ipamorelin acts via a complementary receptor (GHSR-1a) to GHRH analogs like CJC-1295. Combination conditions are studied against GH pulse amplitude via the two pathways.
Specification
| Type | Pentapeptide GH secretagogue / GHSR-1a agonist |
|---|---|
| Sequence | Aib-His-D-2-Nal-D-Phe-Lys-NH₂ |
| CAS Number | 170851-70-4 |
| Molecular Weight | 711.9 g/mol |
| Amino Acids | 5 (pentapeptide) |
| Receptor Target | GHSR-1a (ghrelin receptor) |
| Plasma Half-Life | ~2 hours |
| Form | Lyophilized powder |
| Purity | ≥99% (HPLC verified) |
| Testing | Third-party HPLC, Mass Spec, Endotoxin |
| Storage | -20°C for up to 24 months |
| Solubility | Water-soluble |
| COA | Included with every order |
Frequently asked questions
What is ipamorelin and how does it work?
Ipamorelin is a synthetic pentapeptide (5 amino acids) that selectively binds the Growth Hormone Secretagogue Receptor 1a (GHSR-1a) — also known as the ghrelin receptor — on anterior pituitary somatotrophs. This triggers dose-dependent growth hormone release. It was developed by Novo Nordisk and characterised as the first pentapeptide GH secretagogue with a clean selectivity profile: GH release with no cortisol, ACTH, or prolactin elevation.
How is ipamorelin different from GHRP-6 and GHRP-2?
All three are GHSR-1a agonists acting on GH release. The distinction is selectivity: GHRP-6 and GHRP-2 raise cortisol, ACTH and prolactin alongside GH. Ipamorelin does not — even at concentrations producing maximum GH response. That makes it a cleaner research tool for isolating GH secretion without confounding stress-hormone activity. GHRP-6 also acts strongly on appetite via hypothalamic pathways; ipamorelin's is minimal.
How is ipamorelin characterised in preclinical models?
Preclinical research describes concentration-dependent GH release (ED50 ~80 nmol/kg), no cortisol or prolactin change, and bone growth rate 24% above control (52 vs 42 µm/day) in rat models. Pharmacokinetic characterisation describes GH elevation during nocturnal sleep phases with a ~2-hour half-life and peak GH response at approximately 40 minutes. All preclinical findings should not be extrapolated to human use.
Why is ipamorelin often combined with CJC-1295 in research?
Ipamorelin (GHSR-1a agonist) and CJC-1295 (GHRH-R agonist) work through complementary and synergistic receptor pathways. GHRH and GH secretagogues act at different pituitary receptor sites and their combination produces additive or supra-additive GH pulse amplitude responses. Research protocols studying this combination aim to maximize GH pulse magnitude while preserving pulsatility — an area of active preclinical investigation.
Is ipamorelin FDA-approved?
No. Ipamorelin is not FDA-approved for any indication. It is classified as a research compound and is sold exclusively for in vitro research purposes. No Phase 3 clinical trials have been completed. Some compounding pharmacies have included it in formulations, which the FDA has flagged. It is not intended for human therapeutic use.
How should ipamorelin be stored?
Lyophilized ipamorelin should be stored at -20°C for long-term stability (up to 24 months). Avoid repeated freeze-thaw cycles. The pentapeptide structure is relatively stable in lyophilized form but degrades more rapidly in solution.
For laboratory research use only. Not a drug, supplement, or medical product; not for human or animal use. All findings referenced are from published preclinical/laboratory research.