RESEARCH MONOGRAPH · KDC-MN-081

Hexarelin

May 9, 2026 Kodiac biolabs Research Revised May 30, 2026 2 min read

Our opinion on this compound

65/100

Potent hexapeptide ghrelin mimetic with interesting CD36-mediated cardiac effects beyond the GH-axis story

Hexarelin is Romano Deghenghi's contribution to the GHRP family, a hexapeptide (His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2) that's structurally similar to GHRP-6 with the methyl-tryptophan substitution conferring increased potency at GHSR1a. The Italian Mediolanum group did most of the foundational pharmacology in the 90s.

What we like, and what's genuinely underappreciated, is the off-GHSR cardiac biology. Multiple groups (Locatelli, Bisi, Broglio) have shown that hexarelin has effects on cardiac contractility, vasodilation, and post-MI recovery that don't seem to be mediated by classical GHSR1a or by GH elevation. The current best mechanism candidate is CD36 binding, which is expressed on cardiomyocytes and vascular endothelium and mediates a separate signaling pathway from the pituitary GH receptor. That's an interesting finding because it positions hexarelin as a tool compound for studying CD36-mediated cardiovascular protection independent of GH effects.

What we dont like: the potency comes with tachyphylaxis problems. Repeated dosing causes downregulation of GH response within days, faster than with GHRP-2 or ipamorelin, which limits chronic protocols. Cortisol and prolactin elevation are present at GH-equivalent doses, similar magnitude to GHRP-6. And the cardiac effects, while interesting, are mostly preclinical and the human cardiology data is thin (a few small trials in heart failure from Italian groups, nothing convincing at scale).

Sourcing-wise it's a standard hexapeptide synthesis with the methyl-Trp residue being the main quality variable; the unusual amino acid can be where cheaper vendors cut corners. Stick to suppliers that publish HPLC and verify the modified tryptophan is correctly incorporated. Reputable peptide vendors do this well.

For research on CD36-mediated cardiac signaling, hexarelin is one of the better available tool compounds. For pure GH-axis work, it's competent but not advantageous over GHRP-2 or ipamorelin. The cardiology angle is the more interesting research story and the one most pharmacology surveys miss when they categorize it as just another GHRP.

Evidence: 55
Mechanism: 75
Reliability: 65
Safety: 68
Sourcing: 72
Value: 65
Signal: 62
Staying power: 55

Plain-language summary Intrigue 60 / 100

Hexarelin is a 6-amino-acid ghrelin receptor agonist with the most potent growth hormone-releasing effect of the GHRP family per milligram. Used in cardiology research for cardioprotective effects. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Hexapeptide ghrelin receptor agonist

A hexapeptide GH secretagogue with cardioprotective effects mediated through CD36 binding distinct from the ghrelin receptor.

Abstract

Hexarelin (His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2; CAS 140703-51-1; molecular weight 887.04) is a hexapeptide ghrelin receptor agonist developed in the early 1990s as a more stable GHRP-6 analog. The compound stimulates GH release through GHS-R1a activation and additionally binds CD36, the fatty acid translocase scavenger receptor expressed on cardiomyocytes. The CD36 binding is implicated in cardioprotective effects observed in ischemia-reperfusion models that are distinct from the GH-mediated activity. The compound has been studied in cardiac applications but is not approved for clinical use in any jurisdiction. Pharmacokinetics: plasma half-life 60 to 70 minutes; parenteral administration. Reported research dose ranges in the literature span approximately 100 to 300 micrograms subcutaneously.

Mechanism of action

Ghrelin receptor agonist (GHS-R1a) plus CD36 binding for cardioprotective effects.

Reported research dose ranges

Reported research dose ranges in the literature span approximately 100 to 300 micrograms subcutaneously.

References

Imbimbo BP, et al. Hexarelin: a novel growth hormone-releasing peptide with cardiovascular activity. Endocr Rev 2002.

Read the full monograph

The full reference document covers compound identification, discovery and developmental history, mechanism of action, pharmacokinetics, reported research dose ranges, sourcing and quality verification, reconstitution and handling, stack interaction considerations, and a curated reference list. Available as a research-use-only PDF download.

KDC-MN-081

The full reference document is provided strictly for research use only. It reports research dose ranges from the published literature, not instructions for use in humans or animals.

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FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

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Hexarelin

Abstract

Mechanism of action

Reported research dose ranges

References

Read the full monograph

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Abstract

Mechanism of action

Reported research dose ranges

References

Read the full monograph

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