Ipamorelin
In clinical trialsSelective ghrelin-mimetic GHRP
Also known as: NNC 26-0161
Ipamorelin is a selective growth hormone releasing peptide (GHRP) that stimulates GH release with minimal effect on cortisol, prolactin, or appetite, making it the cleanest of the classic GHRPs.
Molecular & research data
- Sequence
- Aib-His-D-2-Nal-D-Phe-Lys-NH2
- CAS number
- 170851-70-4
- Molecular formula
- C38H49N9O5
- Molecular weight
- 711.85 g/mol
- Half-life
- ≈2 hours
- Primary targets
- GHS-R1a (ghrelin receptor)
- Routes (research)
- Subcutaneous
- Storage
- Lyophilised: −20 °C. Reconstituted: 2–8 °C, use within weeks.
Overview
Ipamorelin is a growth hormone releasing peptide (GHRP) — a synthetic pentapeptide that mimics the hormone ghrelin to trigger growth hormone release. Among the GHRP family, it is prized in research for its selectivity: it raises GH without the off-target effects that characterise older GHRPs.
Mechanism of action
Ipamorelin binds the GHS-R1a receptor (the ghrelin receptor) on the pituitary, stimulating a pulse of growth hormone. What sets it apart is what it doesn’t do — at GH-releasing doses it produces little change in cortisol, prolactin, or appetite, side effects associated with GHRP-6 and, to a lesser extent, GHRP-2.
Because the ghrelin-receptor pathway is distinct from the GHRH pathway, Ipamorelin and GHRH analogs like CJC-1295 are synergistic and commonly researched together.
Common research uses
- Selective stimulation of endogenous growth hormone
- Body composition and recovery research where minimal cortisol/appetite impact is desirable
- As the “clean” reference GHRP in comparisons with GHRP-6, GHRP-2, and Hexarelin
Ipamorelin has been examined in early clinical contexts (including post-operative ileus) but is not an approved therapeutic.
Compare Ipamorelin
Ipamorelin FAQ
Why is Ipamorelin called "selective"?+
Unlike earlier GHRPs, Ipamorelin stimulates growth hormone release with little to no rise in cortisol or prolactin and minimal appetite stimulation, giving it a cleaner profile.
How does Ipamorelin compare to GHRP-6?+
Both act on the ghrelin receptor, but GHRP-6 strongly stimulates hunger and can raise cortisol, whereas Ipamorelin is far more selective for GH release alone.
Is Ipamorelin often combined with other peptides?+
In research it is frequently paired with a GHRH analog such as CJC-1295, because the two receptors act synergistically to amplify the GH pulse.
References
Related peptides
CJC-1295
In clinical trialsLong-acting GHRH analog
CJC-1295 is a synthetic analog of growth-hormone-releasing hormone (GHRH) engineered for a dramatically extended half-life, studied for its ability to raise growth hormone and IGF-1 levels.
GHRP-2
In clinical trialsPotent ghrelin-mimetic GH secretagogue
GHRP-2 (pralmorelin) is a potent growth hormone releasing peptide used clinically as a diagnostic agent in some countries, known for strong GH release with moderate appetite and cortisol effects.
Hexarelin
In clinical trialsHighly potent GHRP with cardiac research interest
Hexarelin is among the most potent growth hormone releasing peptides and is distinguished by additional research interest in cardiac tissue via the CD36 receptor, though it is prone to receptor desensitisation.
Last reviewed: 2026-06-26. Information is provided for research and educational reference only — see our disclaimer.