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Ipamorelin

Ipamorelin is a five-amino-acid ghrelin-receptor agonist. What its one published phase 2 trial found, what regulators and sport bodies say, and what remains unproven.

Content last updated . This page has not been medically reviewed.

Quick answer
Ipamorelin is an investigational compound that stimulates the ghrelin receptor and releases growth hormone (GH). Its main human test was a phase 2 trial in people recovering from bowel surgery, where it was well tolerated but did not significantly beat placebo. No approved ipamorelin medicine was found. This page is education only: no amounts, sourcing or use instructions.

Identity and mechanism

Ipamorelin is a pentapeptide (five amino acids, Aib-His-D-2-Nal-D-Phe-Lys-NH2) described in 1998 as identified within a series of compounds related to growth-hormone-releasing peptide-1. [1] It is a ghrelin-receptor agonist, or "ghrelin mimetic." [2] This is a different route from CJC-1295 and sermorelin, which imitate growth-hormone-releasing hormone. [3][4] FDA also notes that ipamorelin contains unnatural amino acids, which add to the difficulty of characterizing it. [5]

Animal and laboratory evidence (preclinical)

In the original 1998 paper, ipamorelin released GH in rat cells, rats and pigs, and, unlike two older compounds, did not raise the stress hormones ACTH or cortisol in pigs. [1] A 2012 rat study found it sped gastric emptying after abdominal surgery. [6] These are preclinical findings and do not show effects in people.

Human evidence

  • Postoperative ileus, phase 2 (published). 117 patients having bowel resection were randomized to ipamorelin or placebo in a double-blind trial. Median time to first tolerated meal was 25.3 hours with ipamorelin and 32.6 hours with placebo (p = 0.15), so the difference was not statistically significant, and no significant differences were found in secondary efficacy analyses either. The authors called it a small proof-of-concept study. Adverse events occurred in 87.5% and 94.8% of the two groups. [2] Label: no good evidence of benefit for that use.
  • A second, larger registered trial. ClinicalTrials.gov lists a 320-person phase 2 trial for the same kind of recovery, completed, with no results posted on the registry; no journal publication was found. [7] Registered but unreported studies cannot be weighed.
  • Healthy adults, body composition, aging, sleep or recovery: Proper evidence not found. Checked: PubMed (ipamorelin title and abstract search) and ClinicalTrials.gov.

Label for performance, anti-aging and similar claims: marketing claim.

Related guides

Growth-hormone-releasing peptides compared, CJC-1295, GHRP-2, GHRP-6 and hexarelin and peptide safety and adverse events.

Frequently asked questions

Is ipamorelin an approved medicine?

No approved product was found. FDA lists it among bulk substances with compounding safety concerns. [5]

What did the human trial show?

In 117 bowel-surgery patients it was well tolerated but did not differ significantly from placebo on the main measure. [2]

Does ipamorelin build muscle or slow aging?

Proper evidence not found in humans; a 2026 review describes the performance benefits as unproven. [12]

Is ipamorelin banned in sport?

Yes. It is on WADA's 2026 list of prohibited substances. [11]

More details: evidence, limits and cautions

The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.

How to read the evidence labels

Labels used on this page: preclinical (cells or animals only), no good evidence of benefit (for a specific use tested), insufficient evidence, marketing claim, evidence of harm (where a regulator reports it) and Proper evidence not found. A biomarker such as GH or IGF-1 is not a clinical outcome.

Safety and unknowns
Ipamorelin was reported well tolerated for up to 7 days in the bowel-surgery trial, but that is one short study in hospital patients. [2] FDA's compounding page cites a published study that reported serious adverse events including death when ipamorelin was given intravenously for gastric motility, and says it lacks safety information for other injectable routes. [5] A 2018 review of GH secretagogues notes few long-term controlled studies and some concern about higher blood glucose through reduced insulin sensitivity. [8] Proper evidence not found for pregnancy, children, or people with diabetes, cancer or heart disease. Product contents are unverified for unauthorized peptides. [9]
Regulatory and sport status (read 2026-10-22)
Laws change; this is not legal advice.
  • United States: FDA lists ipamorelin acetate in category 2 for outsourcing facilities (503B), added September 29, 2023, and it appears again among substances withdrawn by nominators; FDA cites immunogenicity risk (page current as of 04/22/2026). [5] Compounded drugs are not FDA-approved. [10]
  • Canada: listed by Health Canada among unauthorized injectable peptides it has seized. [9]
  • Sport: WADA's 2026 list names ipamorelin among prohibited growth hormone secretagogues, at all times. [11]
  • EU, UK, Australia: not verified.
References
  1. Raun K et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol 1998. PubMed. Read 2026-10-22.
  2. Beck DE et al. Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients. Int J Colorectal Dis 2014. PubMed. Read 2026-10-22.
  3. Teichman SL et al. Prolonged stimulation of growth hormone and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. J Clin Endocrinol Metab 2006. PubMed. Read 2026-10-22.
  4. Sermorelin: a review of its use in the diagnosis and treatment of children with idiopathic growth hormone deficiency. BioDrugs 1999. PubMed. Read 2026-10-22.
  5. U.S. Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (content current as of 04/22/2026). Read 2026-10-22.
  6. Greenwood-Van Meerveld B et al. Efficacy of ipamorelin, a ghrelin mimetic, on gastric dysmotility in a rodent model of postoperative ileus. J Exp Pharmacol 2012. PubMed. Read 2026-10-22.
  7. ClinicalTrials.gov. NCT01280344 Ipamorelin versus placebo for recovery of gastrointestinal function; Helsinn. Read 2026-10-22.
  8. Sigalos JT, Pastuszak AW. The safety and efficacy of growth hormone secretagogues. Sex Med Rev 2018. PubMed. Read 2026-10-22.
  9. Health Canada. Think twice before injecting peptides bought online: unauthorized products can seriously harm you (public advisory, last updated 2026-04-09). Read 2026-10-22.
  10. U.S. Food and Drug Administration. Compounding and FDA: Questions and Answers. Read 2026-10-22.
  11. World Anti-Doping Agency. 2026 Prohibited List (in force 1 January 2026; the page says each new list is published in October, and the 2027 list was not read). Read 2026-10-22.
  12. Dominikowski A et al. The emerging landscape of performance-enhancing peptides modulating the GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration. Front Endocrinol 2026. PubMed. Read 2026-10-22.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.