{"id":"ipamorelin","name":"Ipamorelin","aliases":["GH secretagogue","ghrelin mimetic","NNC 26-0161"],"url":"https://lyoresearch.com/compounds/ipamorelin","class":{"id":"gh-secretagogues","name":"GH secretagogues (GHRPs)","url":"https://lyoresearch.com/classes/gh-secretagogues"},"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","molecule":{"formula":"C38H49N9O5","molecular_weight":"711.9","cas":"170851-70-4","pubchem_cid":9831659,"note":null},"pharmacokinetics":{"basis":"human","route":"Intravenous infusion in the human study; injected subcutaneously as sold","half_life":"About 2 hours (terminal, intravenous, healthy men)","licensed_regimen":null,"product":null,"source":{"title":"Gobburu JV, et al. Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. Pharm Res 1999;16:1412–1416","url":"https://pubmed.ncbi.nlm.nih.gov/10496658/"}},"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/10496658/"}]},{"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"}],"verbatim":{"text":"Median time to first tolerated meal was 25.3 and 32.6 h in the ipamorelin and placebo groups, respectively (p = 0.15).","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.","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":"Unauthorised medicinal product","note":"No marketing authorisation in any member state. Supplying it for human use is an offence under national medicines law; 'research use only' labels do not change that."},{"region":"United States","status":"Not approved; compounding barred","note":"The advisory committee voted 0–12 against ipamorelin on 29 October 2024. Ipamorelin acetate remains in Category 2 for outsourcing facilities; its 503A nomination is listed as withdrawn (April 2026)."},{"region":"United Kingdom","status":"Unlicensed medicine","note":"Not licensed by the MHRA. Selling or supplying it is an offence under the Human Medicines Regulations 2012; importing a small quantity purely for personal use is not itself an offence, but consignments are seized."},{"region":"Australia","status":"Schedule 4, unapproved","note":"Prescription-only substance not on the ARTG. Obtainable only on prescription (compounded or imported under the Personal Importation Scheme with a prescription). Named in the TGA's April 2026 advisory. Named in NSW law as a prescribed restricted substance."},{"region":"Canada","status":"Not authorised","note":"No Drug Identification Number; selling it is illegal. Among the products Health Canada seized from a domestic vendor in August 2025. Residents cannot import prescription drugs by mail."},{"region":"Sport (WADA)","status":"Prohibited at all times","note":"Growth hormone secretagogue: S2.2.4."}],"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/10496658/","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"}