Hexarelin
A potent synthetic hexapeptide ghrelin receptor agonist studied for growth hormone release and direct effects on cardiac tissue via CD36.
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What is Hexarelin?
Hexarelin is a synthetic hexapeptide growth hormone secretagogue developed in the early 1990s by Mediolanum Farmaceutici as a structural analog of GHRP-6 with enhanced metabolic stability and potency. The peptide differs from GHRP-6 primarily through methylation of the tryptophan residue at position 2 (creating 2-methyl-D-tryptophan), which confers resistance to enzymatic degradation and substantially extends the practical duration of activity.
Hexarelin is notable in research for two distinguishing features. First, it is among the most potent GH-releasers in the GHRP class, producing larger GH pulses than GHRP-6 or ipamorelin at comparable doses. Second, hexarelin has been the subject of substantial cardiac research, with studies suggesting effects on cardiac tissue that appear partially independent of growth hormone release. These cardiac effects are thought to involve the CD36 scavenger receptor in addition to the classical ghrelin receptor.
Mechanism of action
Hexarelin’s mechanisms of action have been investigated across multiple pathways:
- Ghrelin receptor activation: The peptide activates the growth hormone secretagogue receptor (GHS-R1a) on pituitary somatotrophs with potency exceeding earlier GHRPs, stimulating robust growth hormone release.
- CD36 receptor activity: A distinctive feature of hexarelin’s pharmacology is action at CD36, a scavenger receptor expressed in cardiac and vascular tissue, thought to underlie cardiac effects observed independently of GH-mediated pathways.
- Protease resistance via 2-methylation: The methylation at the tryptophan residue protects the peptide from enzymatic cleavage, extending half-life relative to GHRP-6.
- Intermediate selectivity profile: Hexarelin produces some elevation of cortisol, prolactin, and ACTH (less than GHRP-2, more than ipamorelin), reflecting an intermediate position in the GHRP family’s selectivity spectrum.
- Synergy with GHRH analogs: As with other GHRPs, hexarelin produces synergistic GH release when combined with GHRH receptor agonists through complementary receptor pathway activation.
These pathways are characterized in both preclinical models and limited human research.
Research applications
Hexarelin has been investigated across several research domains, with the most active areas including:
- Growth hormone release research: Hexarelin’s potency makes it useful for research contexts requiring robust GH release, including investigations of pituitary function and combination studies with GHRH analogs.
- Cardiac research: The most distinctive research application involves cardiac tissue effects. Studies have examined hexarelin in models of myocardial infarction, ischemia-reperfusion injury, cardiac hypertrophy, and heart failure, with effects thought to involve direct action at cardiac CD36 receptors.
- Combination protocol research: Hexarelin has been studied alongside GHRH analogs (sermorelin, Modified GRF 1-29) to exploit synergistic effects on GH release through dual receptor pathway activation.
- Cardioprotection research: Animal models have examined hexarelin’s protective effects against various forms of cardiac injury, with findings suggesting improvements in cardiac function and reductions in injury markers.
- GHRP family pharmacology: The compound has served as a research reference for studying GHRP selectivity profiles, contributing to broader understanding of the relationship between potency and off-target effects within the ghrelin receptor agonist family.
This compound is intended for laboratory research use only. It has not been approved for human therapeutic use by any regulatory agency.
Storage & reconstitution
In its lyophilized form, hexarelin tolerates ambient temperatures during shipping but should be stored long-term at -20°C, protected from light. Properly stored lyophilized peptide remains stable for 24 months or longer.
Once reconstituted with bacteriostatic water for injection, hexarelin solutions should be stored refrigerated at 2-8°C and used within 28 days. Avoid repeated freeze-thaw cycles, which can degrade peptide structure and reduce activity.
Visual inspection should be performed before each use. The reconstituted solution should be clear and colorless. Reject any solution that appears cloudy, discolored, or contains visible particulate matter.
For step-by-step reconstitution calculations, see our reconstitution calculator.
For laboratory research use only. The compound described on this page is intended exclusively for in vitro research and laboratory experimentation by qualified researchers and is not for human or veterinary use. It is not a drug, food, dietary supplement, or cosmetic, and has not been approved by the FDA, Health Canada, EMA, or any other regulatory authority for the diagnosis, treatment, cure, mitigation, or prevention of any disease or medical condition. The information provided on this page is for educational and reference purposes only and does not constitute medical advice. By accessing this content you confirm that you are a qualified researcher purchasing for legitimate laboratory purposes.