{"id":"ipamorelin","name":"Ipamorelin","aliases":["GH secretagogue","ghrelin mimetic","NNC 26-0161"],"url":"https://lyoresearch.com/compounds/ipamorelin","summary":"Ipamorelin is a synthetic five-amino-acid peptide that stimulates growth-hormone release with little effect on cortisol or prolactin. Small early studies confirmed the hormone release; the only randomised trial — 117 bowel-surgery patients, testing it for post-operative gut recovery — found no benefit, and development stopped. It is not an approved medicine anywhere, and the popular claims about muscle, fat loss and sleep have never been tested in a trial.","overall_grade":"C","overall_grade_meaning":"weak human evidence","human_trials":"1 RCT (negative) + small early-phase","regulatory_status":"Not approved","outcomes":[{"outcome":"Growth hormone release","grade":"C","grade_meaning":"weak human evidence","effect_size":"moderate","adverse":false,"human_studies":"Small early-phase studies","evidence":"Acute, dose-dependent GH rises demonstrated in healthy volunteers in Novo Nordisk's early programme; more selective than GHRP-6, with little cortisol or prolactin rise.","references":[{"citation":"Raun K, et al. Ipamorelin, the first selective growth hormone secretagogue.","where":"Eur J Endocrinol, 1998;139:552–561","url":"https://pubmed.ncbi.nlm.nih.gov/?term=Raun+ipamorelin+selective+growth+hormone+secretagogue+1998"},{"citation":"Gobburu JV, et al. Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers.","where":"Pharm Res, 1999;16:1412–1416","url":"https://pubmed.ncbi.nlm.nih.gov/?term=Gobburu+ipamorelin+pharmacokinetic+human+volunteers+1999"}]},{"outcome":"Post-operative ileus (gut recovery)","grade":"C","grade_meaning":"weak human evidence","effect_size":"not measurable","adverse":false,"human_studies":"1 RCT (n=117)","evidence":"Median time to tolerate a solid meal 25.3 h vs 32.6 h on placebo — not statistically significant (p=0.15). No difference on secondary endpoints. Phase 3 was not pursued.","references":[{"citation":"Beck DE, Sweeney WB, McCarter MD, et al. Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients.","where":"Int J Colorectal Dis, 2014;29:1527–1534","url":"https://link.springer.com/article/10.1007/s00384-014-2030-8"}]},{"outcome":"Body composition","grade":"D","grade_meaning":"no human evidence","effect_size":"not measurable","adverse":false,"human_studies":"None controlled","evidence":"No trial has measured muscle or fat change in people.","references":[]},{"outcome":"Sleep or recovery","grade":"D","grade_meaning":"no human evidence","effect_size":"not measurable","adverse":false,"human_studies":"None","evidence":"Unstudied in humans.","references":[]},{"outcome":"Safety in humans","grade":"C","grade_meaning":"weak human evidence","effect_size":"not measurable","adverse":true,"human_studies":"1 RCT + early-phase","evidence":"Well tolerated over seven days of IV dosing in the ileus trial. No long-term human safety data at the doses and durations used on the grey market.","references":[{"citation":"Beck DE, Sweeney WB, McCarter MD, et al. Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients.","where":"Int J Colorectal Dis, 2014;29:1527–1534","url":"https://link.springer.com/article/10.1007/s00384-014-2030-8"}]}],"regions":[{"region":"European Union","status":"Unapproved medicinal product","note":"No marketing authorisation. Sale for human use is an offence for the seller."},{"region":"United States","status":"Not approved; compounding restricted","note":"FDA has placed ipamorelin among substances that may present significant safety risks in compounding."},{"region":"Sport (WADA)","status":"Prohibited","note":"Growth-hormone secretagogues are banned at all times."},{"region":"Sweden","status":"Unapproved","note":"Treated as a medicine without authorisation."}],"faq":[{"q":"Does ipamorelin build muscle?","a":"Nobody knows. It releases growth hormone in the short term, but no trial has measured muscle or fat change in people taking it. The claim is an inference from the hormone, not a result."},{"q":"Is ipamorelin safe?","a":"It was well tolerated for a week of intravenous dosing in one trial of surgical patients. There is no human data on months of injections, which is how it is used outside medicine."},{"q":"Why was ipamorelin never approved?","a":"Its one proper randomised trial, for post-operative gut recovery, did not meet its endpoint, and the developer stopped. No company has tested it for any other indication."}],"references":[{"cite":"Raun K, et al. Ipamorelin, the first selective growth hormone secretagogue.","where":"Eur J Endocrinol, 1998;139:552–561","url":"https://pubmed.ncbi.nlm.nih.gov/?term=Raun+ipamorelin+selective+growth+hormone+secretagogue+1998","note":"Pharmacology; animal and early human data."},{"cite":"Gobburu JV, et al. Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers.","where":"Pharm Res, 1999;16:1412–1416","url":"https://pubmed.ncbi.nlm.nih.gov/?term=Gobburu+ipamorelin+pharmacokinetic+human+volunteers+1999","note":"Dose–response for GH release in healthy adults."},{"cite":"Beck DE, Sweeney WB, McCarter MD, et al. Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients.","where":"Int J Colorectal Dis, 2014;29:1527–1534","url":"https://link.springer.com/article/10.1007/s00384-014-2030-8","note":"117 patients; primary endpoint not met (p=0.15)."}],"last_reviewed":"2026-09-02","literature_searched_to":"2026-09-02","changelog":[{"date":"2026-09-02","note":"Full page. Added the negative post-operative-ileus RCT, safety row, regional status and FAQ."},{"date":"2026-09-01","note":"Initial publication."}],"license":"CC BY 4.0 — cite as “LYO Research” with a link.","methodology":"https://lyoresearch.com/methodology"}