Research summary

Hexarelin research

A synthetic hexapeptide GH secretagogue, a more metabolically stable GHRP-6 analog.

GH Secretagogue PeptideSynthetic hexapeptide GH secretagogueAAs6MW887.04 g/molCAS140703-51-1StatusNot FDA-approvedNCAABanned

Evidence at a glance

What the research says about Hexarelin

The Hexarelin evidence base cited here is 8 sources — 2 clinical, 4 preclinical, 1 review. Its strongest evidence is human — 2 clinical studies, most recently 1994 ("Growth Hormone-Releasing Activity of Hexarelin in Humans: A Dose-Respons…"). Regulatory status: Not FDA-approved.

Summary

Key takeaways

  • Hexarelin (Examorelin) is a synthetic hexapeptide GH secretagogue — among the most POTENT GHRPs studied — derived from GHRP-6 with a single 2-methyl-Trp substitution for greater stability and potency.
  • Beyond GH release (via the ghrelin/GHS-R1a receptor), it uniquely binds cardiac CD36 receptors, giving a GH-independent cardioprotective effect that's a distinct research interest.
  • It reached Phase II human trials for GH deficiency and heart failure before being discontinued in 2005 for strategic (not safety) reasons — so it has more human data than most research peptides.

Overview

Hexarelin is a six-amino-acid growth-hormone-releasing peptide, developed by Mediolanum Farmaceutici as a more potent successor to GHRP-6. It stimulates GH release through the ghrelin receptor and, distinctively, acts on cardiac CD36 receptors for a heart-protective effect that doesn't depend on GH at all.

It is not FDA-approved; everything below is research context rather than medical guidance.

What Is Hexarelin?

Hexarelin is a synthetic hexapeptide (~887 Da, sequence His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH₂). It is structurally near-identical to GHRP-6 — the one change is a 2-methyl-tryptophan substitution at position 2, which improves proteolytic stability and boosts potency. It's a clean illustration of structure-activity tuning: a single residue swap turns GHRP-6 into the most potent GHRP in the class.

How It Works

Hexarelin binds GHS-R1a on pituitary somatotrophs to trigger a pulse of GH release, peaking around 30 minutes and returning to baseline within a few hours. Separately, it activates cardiac CD36 receptors, producing anti-apoptotic and anti-fibrotic cardioprotective effects independent of growth hormone — the basis for its heart-failure research. As with other GHRPs, pairing it with a GHRH analog produces a markedly larger combined GH pulse.

Side Effects & Safety

Key Studies

  • ALS neuroblastoma model (2023, in vitro): 1 µM protected SOD1-G93A cells against oxidative cytotoxicity (raised Bcl-2, reduced caspase-3, less DNA damage).

Citations

8 peer-reviewed sources

All citations link to the original source (PubMed, journal site, or regulatory filing). Independent research database — no vendor influence on what's cited.

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