Hexarelin — questions, answered plainly.

Hexarelin is a synthetic six-residue growth hormone-releasing peptide (GHRP) developed in the 1990s. It binds the GHS-R1a (ghrelin) receptor and triggers pulsatile GH release in research models. It is not approved as a medicine.

All three are synthetic GHRPs acting at the ghrelin receptor. Hexarelin and GHRP-2 are more potent GH releasers than the later, more selective ipamorelin. Hexarelin literature also documents off-target activity at the cardiac CD36 receptor in animal models.

Massoud et al. 1997 (Clinical Endocrinology, PMID 9425393; n=12) was a controlled human infusion study. Hexarelin counteracted somatostatin-induced GH suppression and showed synergistic GH-releasing activity when combined with GHRH.

Mosa et al. 2017 (Endocrinology, PMID 28977588) studied hexarelin in insulin-resistant MKR mice and reported improved glucose tolerance, lowered triglycerides, enhanced adipocyte differentiation, and corrected body composition. Findings are model-specific.

Like other GHRPs, hexarelin is on the World Anti-Doping Agency prohibited list at all times (S2 — peptide hormones). The compound is referenced here only in research and pharmacology contexts.

Human pharmacology evidence is limited to small early-phase studies. Most efficacy data outside GH-secretion pharmacology come from rodent models; extrapolation to clinical outcomes is not established.