Ipamorelin monograph

Ipamorelin

Overview

Ipamorelin is a synthetic pentapeptide growth hormone secretagogue that was developed as a selective ghrelin receptor agonist. In humans, it has been studied mainly in experimental settings and remains investigational rather than an approved bodybuilding or anti-aging drug. The evidence base for performance use is thin; most real-world dosing, cycling, and stacking practices come from community anecdote rather than clinical trials.

Pharmacokinetics & Mechanism

• Class: Selective growth hormone secretagogue peptide; ghrelin receptor agonist / growth hormone-releasing peptide
• Mechanism of action: Ipamorelin stimulates growth hormone release from the anterior pituitary by activating the ghrelin receptor (growth hormone secretagogue receptor, GHS-R1a). Compared with older secretagogues, it is generally described as more selective for GH release with less prolactin and cortisol stimulation in available experimental literature, but meaningful human outcome data for physique/performance use are lacking.
• Target(s): Primary target: ghrelin receptor / growth hormone secretagogue receptor 1a (GHS-R1a) in the pituitary and hypothalamic axis. Downstream pathway: pulsatile growth hormone release with secondary increases in IGF-1 depending on dose/exposure and baseline physiology.
• Route(s) of administration: Subcutaneous injection is the practical route used in studies and in the bodybuilding community. Not established for oral use; peptide degradation makes oral bioavailability poor. Intranasal and other routes are not well established for ipamorelin.
• Onset: Not well established in humans for performance use. GH secretagogue effects are generally expected within minutes after injection, with measurable GH pulses occurring soon after dosing in experimental settings.
• Half-life: Short acting. Human half-life is not well established in widely cited clinical references; community reports often quote roughly 1–2 hours, but this is not a robust clinical pharmacokinetic value. No long-acting/depot ipamorelin variant is well established in standard medical references; any extended-release or combined formulations are nonstandard and not well validated.
• Metabolism / clearance: Not well established in humans. As a peptide, ipamorelin is expected to undergo enzymatic peptide hydrolysis and rapid systemic clearance rather than hepatic CYP metabolism; renal/hepatic disease-specific clearance data are not well established.