Ipamorelin in human studies
| Study | Who | Route, duration | What was found |
|---|---|---|---|
| Gobburu 1999 [1], PMID 10496658 | healthy men, 8 per dose level | IV infusion, once, five levels | half-life 2 h; one GH peak at 0.67 h |
| Beck 2014 [2], PMID 25331030 | 114 adults after bowel resection | IV, in hospital, up to 7 days | first meal 25.3 vs 32.6 h, p = 0.15; well tolerated |
| Helsinn [3], NCT01280344 | 320 adults after bowel resection | IV, in hospital, three arms vs placebo | completed 2014; no results posted |
Table 1. Every published human study of ipamorelin, with the PubMed or registry number. Study data, not a recommendation.
The only study that gave ipamorelin to healthy people and measured growth hormone was published in 1999 by Gobburu, Agersø, Jusko and Ynddal. Eight healthy men per level received a 15-minute intravenous infusion at one of five levels. Exposure rose in proportion to the amount given, the terminal half-life was 2 hours and clearance 0.078 l/h/kg. At every level, GH rose in one episode that peaked at 0.67 hours and fell back to negligible levels [1]. The men differed more in their GH response than in the way they cleared the drug.
The two later trials were run by Helsinn for a different purpose, postoperative ileus, and they did not measure GH. In the proof-of-concept trial, 114 adults recovering from bowel resection received ipamorelin or placebo intravenously from the first day after surgery to day 7 or discharge. Median time to a first tolerated solid meal was 25.3 hours on ipamorelin and 32.6 on placebo (p = 0.15), and treatment-emergent adverse events were reported in 87.5 % and 94.8 % of patients [2].
The trial that followed enrolled 320 patients across three intravenous arms against placebo. The registry marks it completed in May 2014 with no results posted [3].
There were no significant differences between ipamorelin and placebo in the key and secondary efficacy analyses.
Ipamorelin in animal studies
Most of what is known about repeated administration comes from animals. The table lists each study by species, route and duration.
| Study | Animals | Route, duration | What was found |
|---|---|---|---|
| Raun 1998 [4], PMID 9849822 | conscious swine | single administrations | no ACTH or cortisol rise at over 200 times the ED50 |
| Johansen 1999 [5], PMID 10373343 | adult female rats | SC, 15 days | faster tibial growth, total IGF-1 unchanged |
| Svensson 2000 [6], PMID 10828840 | young female rats, n = 7 | SC minipump, 12 weeks | more bone mineral and body weight |
| Andersen 2001 [7], PMID 11735244 | older female rats on a steroid | SC, 3 months | bone formation ×4 vs steroid alone |
| Venkova 2009 [8], PMID 19289567 | rats after gut surgery | IV, up to 2 days | more food intake after surgery |
| Greenwood-Van Meerveld 2012 [9], PMID 27186127 | rats after gut surgery | IV, once | faster gastric emptying |
| Lu 2024 [10], PMID 39043357 | ferrets given cisplatin | IP, up to 72 h | no effect on vomiting |
| Ankersen 1998 [11], PMID 9733495 | dogs | oral, once | basal GH up more than 10-fold |
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Table 2. Ipamorelin in animal studies, from the PubMed abstracts. Animal data do not transfer to people.
The pattern is consistent. In swine, Novo Nordisk found ipamorelin released GH about as potently as GHRP-6 without the ACTH and cortisol rise that GHRP-6 and GHRP-2 caused [4]. In rats, repeated injections for 15 days sped up tibial growth without changing total IGF-1, and the pituitary answered a test stimulus slightly less afterwards [5]. Twelve weeks by minipump raised bone mineral content by making bones bigger, not denser [6], and 3 months of injections counteracted the loss of muscle strength and bone formation caused by a glucocorticoid [7].
The gut studies used intravenous administration. After abdominal surgery in rats, repeated administration increased food intake [8] and sped up gastric emptying [9]. In ferrets, ipamorelin did not stop cisplatin-induced vomiting [10]. In dogs, oral administration raised basal GH more than tenfold [11], and nasal ipamorelin reached about 20 % bioavailability in rats [12].
What was never studied
The gaps are larger than the table. No human study has given ipamorelin by any route other than the vein, for longer than 7 days, outside a hospital, or together with CJC-1295. One volunteer did receive it nasally in a 2015 anti-doping study, but that study tracked metabolites in urine and measured no effect [13]. No human study measured muscle, fat or sleep.
The albumin-bound partner of the blend has its own page, CJC-1295 peptide.
Where it stands in 2026
Ipamorelin is a five-residue peptide, Aib-His-D-2-Nal-D-Phe-Lys-NH2, designed at Novo Nordisk and published in 1998 as the first selective GH secretagogue [4]. It is not an approved drug anywhere: the FDA has not approved it and neither has the EMA. On September 29, 2023, the FDA placed ipamorelin acetate in category 2 of the bulk substances nominated for compounding, with the stated concern of immunogenicity for certain routes [14].
It is prohibited in sport under class S2 of the WADA list [15]. What remains is a research reagent with a defined sequence, a defined mass and a short study record, sold for research use only, not for human or veterinary use. OXpeptides, the shop run by the publisher of this site, lists ipamorelin on its own as a 5 mg vial. This page reports that record and gives no dose or protocol.
