● pepmg Research Desk · Peer-reviewed evidence review
What the research says about ipamorelin
A neutral summary of the peer-reviewed literature on ipamorelin, a selective growth-hormone secretagogue studied mainly in animal and in-vitro models, with only small early human trials. Research use only.
Limited evidence — Early or small human data, or strong preclinical work. This describes the state of the published literature, not a claim that this compound works, is safe, or is for human use. Research use only.
The short version
- Ipamorelin is a selective growth-hormone secretagogue (a ghrelin-receptor agonist) studied mostly in animal and in-vitro models, with only small early-phase human trials [1][2][3].
- In animal and cell studies it released growth hormone with a selectivity that, unlike some related peptides, did not raise ACTH or cortisol [1].
- The largest human trial, a proof-of-concept phase 2 study in postoperative patients, reported no statistically significant benefit over placebo on its main endpoints [3].
- This page reports what the studies measured. It is not medical advice, an efficacy or safety claim, or dosing guidance. Research use only.
What ipamorelin is
Ipamorelin is described in the literature as a synthetic pentapeptide and a potent, selective growth-hormone secretagogue that acts through a ghrelin-like (growth-hormone-releasing-peptide) receptor to stimulate release of the body's own growth hormone [1]. It is sold by third-party research-chemical vendors and is not an approved medicine; it is offered for laboratory and research use only.
Most of what is known about ipamorelin comes from laboratory and animal pharmacology rather than clinical outcome trials [1][6].
What the preclinical and early human research has measured
Preclinical onlyIn its founding characterization, ipamorelin released growth hormone from rat pituitary cells and in anaesthetised rats and conscious swine with potency and efficacy similar to the reference peptide GHRP-6 [1]. A distinguishing finding was selectivity: unlike GHRP-6 and GHRP-2, ipamorelin did not raise ACTH or cortisol levels even at doses far above those needed for growth-hormone release [1]. In adult female rats, ipamorelin dose-dependently increased longitudinal bone growth and body-weight gain, though it did not change total IGF-I levels in that study [4], and chronic treatment altered somatotroph (growth-hormone cell) content in the pituitary [5].
Human data are limited to small early studies. A pharmacokinetic-pharmacodynamic trial in healthy male volunteers characterized ipamorelin's disposition, reporting a short terminal half-life of about 2 hours and a single episode of growth-hormone release after infusion [2].
What the trials report on safety and adverse events
Limited evidenceThe one comparatively large human trial was a proof-of-concept, phase 2, randomized, double-blind, placebo-controlled study of intravenous ipamorelin for postoperative ileus after bowel resection, enrolling 117 patients [3]. It reported that ipamorelin was well tolerated, with any treatment-emergent adverse events in about 87.5% of the ipamorelin group versus about 94.8% of the placebo group [3]. However, the study reported no statistically significant difference from placebo on its key efficacy endpoint (median time to first tolerated meal about 25.3 versus 32.6 hours, p about 0.15) and noted it was small and enrolled a broad range of patients [3].
A review of growth-hormone secretagogues in body-composition management noted that, although these compounds are potent stimulators of growth hormone and IGF-1, clinical efficacy data for uses such as muscle gain or fat loss are largely lacking [6]. There are no controlled human trials establishing the safety of ipamorelin for the anti-aging or physique-related uses for which it is marketed.
This is not medical advice. The human safety of ipamorelin for its marketed uses is not established; consult a qualified professional and read the studies directly.
How strong is the evidence
Because ipamorelin's effects have been characterized mainly in animal and in-vitro models, with only small early human pharmacology studies and one proof-of-concept trial that did not meet its endpoints, the evidence base is characterized as limited [1][2][3]. "Limited" describes the state of the research, not a judgment of whether ipamorelin works or is safe.
Nothing here is dosing, medical, or safety guidance. Read the studies themselves and consult a qualified professional. This page is a map to the evidence, not a recommendation.
Sources · 6
- Ipamorelin, the first selective growth hormone secretagogue.
- Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers.
- Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients.
- Ipamorelin, a new growth-hormone-releasing peptide, induces longitudinal bone growth in rats.
- Influence of chronic treatment with the growth hormone secretagogue ipamorelin, in young female rats: somatotroph response in vitro.
- Beyond the androgen receptor: the role of growth hormone secretagogues in the modern management of body composition in hypogonadal males.
pepmg summarizes the peer-reviewed literature and links to every source — it sells nothing, ships nothing, and gives no medical, dosing, or human-use guidance. Don't just trust this summary: follow any citation to its source and read it yourself. Research use only.