Hexarelin

Overview

Hexarelin is a synthetic hexapeptide growth hormone secretagogue, structurally related to GHRP-6, that binds the GH secretagogue receptor (GHSR1a) — the same receptor family as ipamorelin — but has drawn separate research interest for cardiac effects that appear to occur independently of its GH-releasing activity, including binding to the non-GHSR receptor CD36 on cardiac tissue.

Proposed Mechanism of Action

Beyond conventional GHSR1a-mediated growth hormone release, the cardioprotective literature on hexarelin points to a GH-independent mechanism: direct action on cardiomyocytes (heart muscle cells) via CD36 and protein kinase C pathways, distinct from its endocrine effects on the pituitary.

Research Context

The cited study induced experimental myocardial infarction (heart attack) in rats and compared hexarelin treatment to recombinant human growth hormone and untreated controls. Hexarelin improved cardiac function and reduced peripheral vascular resistance to a degree comparable to exogenous GH — notable because it suggests the benefit isn't simply downstream of more circulating growth hormone. This finding is part of a broader published research thread (multiple other cited papers in our source search examine hexarelin's effects on ischemia-reperfusion injury, cardiomyocyte apoptosis, and cardiac fibrosis in animal models) rather than an isolated result.

Limitations of the Current Evidence

• The cardioprotective research base is exclusively animal (primarily rat and mouse) models of induced cardiac injury; we found no human clinical trial data specifically for cardioprotection in the sources reviewed for this profile.
• As with other GH secretagogues, hexarelin also affects cortisol and prolactin release in some studies — a less selective hormonal profile than newer secretagogues like ipamorelin, worth factoring into any mechanistic comparison between compounds.