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Ipa2.5
Ipamorelin Research
Mostly mechanism / observationalLimited safety
12 peer-reviewed studies
What the evidence says
Mostly mechanism / observational
Most Ipamorelin studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from mixed-quality randomised trials published 1998–2024 with a typical study size of 114 participants.
Based on 12 studies · 2 RCTs · 154 total participants
Confidence
Low
By outcome
Growth hormone & body composition
Mostly mechanism / observational4 studies
GI motility & postoperative ileus
Mostly mechanism / observational3 studies
Slowing down
Only 1 study in the last 5 years
199820112024
1RCTn=114 · medium study2014
There were no significant differences between ipamorelin and placebo in the key and secondary efficacy analyses.
Beck DE, Sweeney WB, McCarter MD. · Int J Colorectal Dis (2014)
Phase-2, multicenter, double-blind, placebo-controlled RCT in 114 bowel-resection patients (NCT00672074) — the only published human efficacy trial
Ipamorelin 0.03 mg/kg IV twice daily for up to 7 days was well tolerated (adverse-event rates similar to placebo)
PRIMARY ENDPOINT FAILED: median time to first tolerated meal 25.3 h (ipamorelin) vs 32.6 h (placebo), p = 0.15 — not significant
By a rational approach we were able to reduce the size of the lead compound ipamorelin and simultaneously to reduce hydrogen-bonding potential ... while retaining in vivo potency in swine.
Hansen TK, Ankersen M, Hansen BS, Raun K, Nielsen KK, Lau J, Peschke B, Lundt BF, Thøgersen H, Johansen NL, Madsen K, Andersen PH. · J Med Chem (1998)
Medicinal-chemistry program using ipamorelin as the lead compound to design orally active GH secretagogues
Screened in a rat pituitary assay and tested for in-vivo potency in swine and oral bioavailability in dogs
Most analogues showed 10-55% oral bioavailability; most potent compound ED50 ~30 nmol/kg IV in swine
Ipamorelin dose-dependently increased LGR from 42 microm/day in the vehicle group to 44, 50, and 52 microm/day in the treatment groups (P<0.0001).
Johansen PB, Nowak J, Skjaerbaek C, Flyvbjerg A, Andreassen TT, Wilken M, Orskov H. · Growth Horm IGF Res (1999)
Subcutaneous ipamorelin (18-450 µg/day, 3×/day for 15 days) in adult female rats dose-dependently increased longitudinal bone growth rate and body-weight gain
Notably, treatment did NOT change total IGF-I, IGFBPs, or serum bone-turnover markers
Authors explicitly note that any role in treating growth-retarded children 'requires demonstration in future clinical studies'
Ipamorelin induces the release of GH at all dose levels with the concentration (SC50) required for half-maximal GH stimulation of 214 nmol/L and a maximal GH production rate of 694 mIU/L/h.
Gobburu JV, Agersø H, Jusko WJ, Ynddal L. · Pharm Res (1999)
Dose-escalation human PK/PD trial: 5 IV infusion rates (4.21-140.45 nmol/kg over 15 min), 8 healthy male volunteers per dose level
Confirmed that ipamorelin reliably triggers a single episode of GH release in humans at every dose tested, peaking ~0.67 h
PK was dose-proportional with a short ~2 h terminal half-life — the GH effect is a brief pulse, not sustained
These data suggest that, at least in the young female rat, the GHS Ipamorelin is able to exert a dynamic control effect on the somatotroph population and on GH hormone content.
Jiménez-Reina L, Cañete R, de la Torre MJ, Bernal G. · Histol Histopathol (2002)
21-day in-vivo ipamorelin dosing followed by in-vitro analysis of rat pituitary somatotroph cells
Increased the volume density of secretion granules in somatotrophs (vs saline)
Did not change somatotroph cell percentage or the ratio of staining cell types
Ipamorelin is a synthetic peptide with GH releasing properties. We wished to study the metabolic effects of Ipamorelin and GH on selected hepatic measures of alpha-amino-nitrogen conversion during steroid-induced catabolism.
Aagaard NK, Grøfte T, Greisen J, Malmlöf K, Johansen PB, Grønbaek H, Ørskov H, Tygstrup N, Vilstrup H. · Growth Horm IGF Res (2009)
Rat model of prednisolone-induced catabolism comparing ipamorelin vs GH on nitrogen balance and hepatic urea synthesis
Probed whether the GH-axis effects of ipamorelin could mitigate steroid-driven nitrogen wasting
Metabolic/anti-catabolic animal pharmacology — not a clinical efficacy study
Ipamorelin (0.014 µmol/kg intravenous) resulted in a significant acceleration of gastric emptying ... through the stimulation of gastric contractility by activating a ghrelin receptor-mediated mechanism involving cholinergic excitatory neurons.
Greenwood-Van Meerveld B, Tyler K, Mohammadi E, Pietra C. · J Exp Pharmacol (2012)
Rat gastroparesis/postoperative-ileus model: IV ipamorelin accelerated delayed gastric emptying after abdominal surgery
Reversed the surgery-induced inhibition of acetylcholine- and field-stimulation-induced gastric smooth-muscle contraction in isolated tissue
Identified a ghrelin-receptor + cholinergic-excitatory-neuron mechanism for the prokinetic effect
Anamorelin and ipamorelin administered i.p. had beneficial effects in alleviating cisplatin-induced weight loss during delayed phase.
Lu Z, Ngan MP, Liu JYH, Yang L, Tu L, Chan SW, Giuliano C, Lovati E, Pietra C, Rudd JA. · Physiol Behav (2024)
Ferret model of cisplatin chemotherapy: intraperitoneal ipamorelin (1-3 mg/kg) vs vehicle, dosed before cisplatin and every 24 h
Ipamorelin did not affect acute or delayed emesis but reduced associated cisplatin-induced weight loss in the delayed phase (48-72 h) by ~24%
Ipamorelin also inhibited electrical-field-stimulation-induced contractions of isolated ferret ileum (consistent with its ghrelin-receptor GI activity)