A selective GHS-R1a agonist notable for releasing growth hormone without the cortisol and prolactin rise seen with earlier secretagogues. Human trials exist but are small and focused on postoperative ileus.
Ipamorelin makes the pituitary gland release a pulse of growth hormone. It does this by mimicking ghrelin, the hormone the stomach releases when empty. What made it interesting to researchers is its selectivity — earlier compounds in the same class also pushed up cortisol and prolactin, while ipamorelin largely did not in the published animal work. It has been tested in humans mainly as a treatment for slowed gut motility after surgery, not for growth hormone effects.
Ipamorelin is the pentapeptide Aib-His-D-2-Nal-D-Phe-Lys-NH2, a synthetic agonist at the growth hormone secretagogue receptor 1a (GHS-R1a). Receptor activation is Gq-coupled: phospholipase C activation generates IP3 and DAG, releasing intracellular calcium in pituitary somatotrophs and triggering GH exocytosis. It also suppresses somatostatin tone at the hypothalamic level, amplifying endogenous GH pulse amplitude while preserving pulsatility — the pharmacologic argument for secretagogues over exogenous recombinant GH. Unlike GHRP-6 and GHRP-2, ipamorelin showed no significant ACTH or prolactin release at GH-releasing doses in the original characterization studies, attributed to its lack of activity at the receptors mediating those responses.
Research areas
Community-specified data
Source note: May start at 500mcg daily and titrate up. If water retention, lower dose
Not medical guidance. These third-party figures have not been independently verified, clinically reviewed, or endorsed by DB Peptide. They may be inaccurate or unsafe and should not replace product labelling or advice from a qualified clinician.
Every protocol below is reproduced from a published study or approved labelling, with its source named. These are records of what was studied — not recommendations, and not a suggestion that any of them is appropriate for any person.
| Protocol as reported | Source |
|---|---|
| Intravenous doses producing dose-dependent GH release in swine, characterized across a 0.4–100 µg/kg rangeAnimal characterization study. This is the source of the widely quoted dose range; it is not a human dosing recommendation. | Raun et al., European Journal of Endocrinology 1998 |
| Intravenous infusion in the postoperative ileus phase 2 programmeRoute and indication differ substantially from how the compound is discussed outside clinical settings. | Postoperative ileus phase 2 trial protocol |
Phase 2 trials completed in postoperative ileus; the programme did not meet its primary endpoint and did not advance. No trials of GH-related endpoints beyond phase 1.
Original characterization in swine and rats established dose-dependent GH release without ACTH, cortisol or prolactin elevation at effective doses.
Evaluated for acceleration of gastrointestinal recovery after bowel resection. The programme did not proceed to registration.
They act on different receptors in the same axis. Ipamorelin is a ghrelin receptor agonist and CJC-1295 is a GHRH analogue. Studies of GHRP plus GHRH co-administration report greater GH release than either alone, which is the pharmacologic rationale. Note that this synergy is documented for the drug class generally, not for this specific pair in a controlled human trial.
Medical disclaimer
This page is for informational and research purposes only. Nothing here constitutes medical advice. The compounds discussed are research chemicals. Consult a qualified clinician before starting any protocol.
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