What Is Ipamorelin?
Ipamorelin is a synthetic pentapeptide (five amino acids) studied in preclinical research as a selective growth hormone secretagogue. It is not an FDA-approved drug.
The short answer
Ipamorelin is a lab-synthesized peptide that acts on the ghrelin/growth-hormone-secretagogue receptor (GHS-R1a). In the research literature it is described as one of the more selective secretagogues — it stimulates growth-hormone release with comparatively little effect on other hormones such as cortisol or prolactin, which is a large part of why it is studied alongside GHRH analogs like CJC-1295. It is supplied as a lyophilized powder and verified by analytical testing before use.
Composition and specifications
| Compound | Ipamorelin |
|---|---|
| Class | Growth hormone secretagogue (GHS-R1a agonist); pentapeptide |
| Also known as | CAS 170851-70-4 |
| Sequence / length | 5 amino acids (pentapeptide) |
| CAS number | 170851-70-4 |
| Molecular weight | 711.85 g/mol |
| Purity (typical) | ≥99.1% |
| Appearance | White lyophilized powder; water-soluble |
Values above reflect the compound's published specification. As with any research material, the definitive confirmation of identity and purity for a given lot is the mass-spectrometry and HPLC data on its Certificate of Analysis.
How it is described mechanistically
Ipamorelin binds the growth-hormone-secretagogue receptor (GHS-R1a), the same receptor targeted by the hormone ghrelin. In research models this binding is associated with pulsatile growth-hormone release from the pituitary. Its research interest comes from selectivity: unlike some earlier secretagogues, it is characterized as producing a growth-hormone pulse with minimal activation of adrenocorticotropic pathways.
What has research examined?
Most published ipamorelin work is preclinical — animal and cell-based rather than large controlled human trials. Areas investigated include:
- Growth-hormone-release signaling and receptor selectivity
- Comparisons with other secretagogues (e.g. GHRP-2, GHRP-6)
- Combined GHRH-analog + secretagogue signaling (studied alongside CJC-1295)
- Bone and body-composition research models
These describe research directions, not established human effects. Human clinical evidence for ipamorelin specifically is limited.
How is it characterized and tested?
Two questions matter most about any peptide sample in a research context: is it the right molecule, and how pure is it. Those are answered by analytical testing — commonly mass spectrometry for identity and HPLC for purity — with both reported on a batch-specific Certificate of Analysis (COA). An independent, published COA lets a researcher confirm identity and purity before beginning work. See peptide handling and storage for how samples are kept stable once received.
Primary literature: browse peer-reviewed studies on Ipamorelin at PubMed.
Common questions
Is ipamorelin approved for human use?
No. Ipamorelin is not an FDA-approved drug. Research-grade material is intended for laboratory research use only.
What is the difference between ipamorelin and sermorelin?
They act on different receptors. Ipamorelin is a growth-hormone-secretagogue-receptor (ghrelin receptor) agonist, while sermorelin is a GHRH analog that acts on the GHRH receptor. In the literature the two mechanisms are sometimes studied together.
Why is ipamorelin often studied with CJC-1295?
Because the two act on complementary pathways — a GHRH analog plus a secretagogue — which is why they frequently appear together in growth-hormone research models. This is a description of the literature, not a dosing recommendation.