Ipamorelin is a synthetic pentapeptide and selective growth hormone secretagogue (GHS), developed as a highly specific agonist of the GH secretagogue receptor (GHS-R). Unlike earlier GHRPs, ipamorelin stimulates GH release without significantly elevating cortisol, ACTH, or prolactin. Below is a curated selection of peer-reviewed studies investigating its properties.
2014
Prospective Randomised Controlled Proof-of-Concept Study of Ipamorelin for the Management of Postoperative Ileus in Bowel Resection Patients
PubMed / International Journal of Colorectal Disease
This randomised controlled clinical trial evaluated ipamorelin as a prokinetic agent in patients undergoing bowel resection surgery. Ipamorelin treatment was associated with accelerated return of gastrointestinal function post-surgery, reduced ileus duration, and was well tolerated, supporting further clinical development as a post-surgical GI motility agent.
View Paper →2012
Efficacy of Ipamorelin, a Ghrelin Mimetic, on Gastric Dysmotility in a Rodent Model of Postoperative Ileus
PMC / Journal of Experimental Pharmacology
This preclinical study demonstrated that ipamorelin significantly accelerated gastric emptying and normalised colonic transit in rats with surgically induced postoperative ileus. The mechanism was found to involve cholinergic excitatory neurons via the ghrelin receptor, supporting ipamorelin’s potential as a prokinetic research agent.
View Paper →2002
Influence of Chronic Treatment with Ipamorelin on Somatotroph Response In Vitro
PubMed / Growth Hormone & IGF Research
This study examined the effects of chronic ipamorelin treatment on pituitary somatotroph cell populations in young female rats over 21 days. Ipamorelin increased the volume density of secretion granules in GH-producing cells without altering their ultrastructure, demonstrating sustained GH secretagogue activity with chronic administration.
View Paper →2001
Ipamorelin Counteracts Glucocorticoid-Induced Decrease in Bone Formation in Adult Rats
PubMed / Growth Hormone & IGF Research
This study found that ipamorelin significantly counteracted the catabolic effects of glucocorticoid treatment on bone and muscle in adult rats. Animals receiving both glucocorticoid and ipamorelin showed a four-fold increase in periosteal bone formation rate and improved muscle tetanic tension compared to those receiving glucocorticoid alone.
View Paper →2000
The GH Secretagogues Ipamorelin and GHRP-6 Increase Bone Mineral Content in Adult Female Rats
Journal of Endocrinology
This study compared ipamorelin and GHRP-6 in adult female rats over 12 weeks, finding both compounds increased bone mineral content as measured by DXA. The findings support a GH-mediated mechanism for ipamorelin’s effects on skeletal mineralisation and provide early evidence for its potential in bone density research.
View Paper →1998
Ipamorelin — The First Selective Growth Hormone Secretagogue
European Journal of Endocrinology (Novo Nordisk / Semantic Scholar)
The foundational pharmacological characterisation of ipamorelin, demonstrating potent GH release via a GHRP-like receptor without elevating ACTH or cortisol — even at doses 200-fold above its effective GH-releasing dose. This selectivity profile distinguishes ipamorelin from GHRP-2 and GHRP-6 and underpins its subsequent research interest.
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