Ipamorelin

Two of the ten cited papers are human studies: a 1999 pharmacokinetic-pharmacodynamic modelling study in volunteers and a 2014 randomised, placebo-controlled phase 2 proof-of-concept trial in patients after bowel resection. The other eight are preclinical, published between 2012 and 2024. They comprise a rodent model of postoperative ileus, a ferret study of cisplatin, a study of the reproductive axis in a cichlid fish, a pain study of ghrelin mimetics, a chemistry paper on boron-containing ghrelin-receptor agonists, and three anti-doping papers on identifying secretagogues and their metabolites.

In the rodent ileus model, ipamorelin accelerated gastric emptying, which the authors attributed to ghrelin-receptor stimulation of gastric contractility through cholinergic excitatory neurons. The phase 2 trial took the question to patients and found no significant difference from placebo in its key or secondary analyses, while reporting the peptide as well tolerated. The modelling study characterised ipamorelin's disposition and growth hormone response across a range of doses. In ferrets, ipamorelin and anamorelin both inhibited the loss of body weight caused by cisplatin, and in the cichlid fish, serum luteinising hormone and 11-ketotestosterone rose relative to controls. The pain study implicated ghrelin-receptor mechanisms in visceral and somatic hypersensitivity when the colon was not actively inflamed. The anti-doping work identified glycine-modified analogues of ipamorelin and related secretagogues in seized material, and found that detection windows in urine depend on individual metabolism, formulation and route.

The human evidence is thin: one controlled trial in patients, negative on its outcome analyses, and a modelling paper from 1999. The rodent motility result was not matched by a difference from placebo in that trial. Half of the preclinical papers concern detection or chemistry rather than biological effects, and the ferret, fish and pain findings each come from a single experiment that has not been repeated in the cited record.