Hexarelin — Growth hormone secretagogue — synthetic hexapeptide GHRP class / GHS-R1a agonist with cardioprotective properties
Hexarelin is a synthetic hexapeptide (His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2) that acts as a potent GHS-R1a agonist with the strongest GH-releasing potency among the GHRP class (more potent than GHRP-6 and GHRP-2). Unlike GHRP-6, it does not significantly stimulate appetite (lower ghrelin-pathway activity at the hypothalamic level). Key mechanism: GHS-R1a activation in the pituitary and hypothalamus triggers pulsatile GH release; additionally, GHS-R1a is expressed in cardiac tissue where hexarelin exerts direct cardioprotective effects independent of GH secretion — reduces ischemia-reperfusion injury, improves cardiac contractility, and activates PAI-1 (protective anti-apoptotic pathway in cardiomyocytes). Notably, hexarelin's GH-releasing effect undergoes rapid tachyphylaxis with continuous dosing — cycling is essential.
Overview
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Compound Class
Growth hormone secretagogue — synthetic hexapeptide GHRP class / GHS-R1a agonist with cardioprotective properties
Mechanism of Action
Hexarelin is a synthetic hexapeptide (His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2) that acts as a potent GHS-R1a agonist with the strongest GH-releasing potency among the GHRP class (more potent than GHRP-6 and GHRP-2). Unlike GHRP-6, it does not significantly stimulate appetite (lower ghrelin-pathway activity at the hypothalamic level). Key mechanism: GHS-R1a activation in the pituitary and hypothalamus triggers pulsatile GH release; additionally, GHS-R1a is expressed in cardiac tissue where hexarelin exerts direct cardioprotective effects independent of GH secretion — reduces ischemia-reperfusion injury, improves cardiac contractility, and activates PAI-1 (protective anti-apoptotic pathway in cardiomyocytes). Notably, hexarelin's GH-releasing effect undergoes rapid tachyphylaxis with continuous dosing — cycling is essential.
Regulatory Status
NOT FDA approved. NOT EMA approved. Investigational peptide. No approved indication in any jurisdiction.
Evidence Level
C — Human pharmacological studies confirm potent GH-releasing effect (PMID: 7490562, 7883661); Phase 2 cardiac data in humans is limited; no Phase 3 RCTs completed for any indication; not FDA/EMA approved.