Hexarelin (also called examorelin) is a synthetic hexapeptide growth hormone secretagogue with the sequence His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2 that stimulates growth hormone (GH) release by activating the ghrelin receptor (GHS-R1a) and also binds the scavenger receptor CD36. Developed as a more potent analogue of GHRP-6, it is widely used in laboratory research as a probe for growth hormone regulation and, distinctively, for CD36-mediated cardiovascular signaling. This article summarizes its background, mechanism, the published literature, and how it is handled in the laboratory. As of 2026, hexarelin remains an actively cited reference compound in the peer-reviewed literature on GH secretagogue receptors and myocardial protection.
What Is Hexarelin?
Hexarelin is a six-amino-acid peptide (molecular formula C47H58N12O6) developed in the early 1990s from structure-activity work on growth hormone-releasing peptide-6 (GHRP-6). The addition of a 2-methyl group to the D-tryptophan residue increases its metabolic stability and receptor-binding affinity relative to GHRP-6, making it one of the more potent peptidyl secretagogues characterized in that era. Its compact sequence confers relative resistance to enzymatic degradation compared with longer peptides, a property that contributed to its use across cell-culture, animal, and human research models. Like other members of the GHRP family, hexarelin acts on a receptor distinct from that of growth hormone-releasing hormone (GHRH), which makes it a useful tool for dissecting the separate arms of GH control.
Mechanism of Action
Hexarelin is an agonist at the growth hormone secretagogue receptor type 1a (GHS-R1a), the same G protein-coupled receptor targeted by the endogenous hormone ghrelin, expressed in the anterior pituitary and hypothalamus. Receptor activation engages the phospholipase C signaling cascade, raising intracellular calcium in pituitary somatotrophs and driving GH release. In rat models, hexarelin-stimulated GH secretion has been attributed to three non-mutually-exclusive mechanisms: a direct action on the pituitary of minor relevance; an indirect action involving release of GHRH; and an action through an as-yet-unidentified hypothalamic factor that acts synergistically with GHRH.
Beyond the pituitary, hexarelin binds a second, structurally unrelated receptor: the scavenger receptor CD36, expressed in cardiomyocytes and microvascular endothelial cells. In a foundational 2002 study published in Circulation Research, rat cardiac membranes were labeled with a radioactive photoactivatable derivative of hexarelin, and the binding protein was purified and sequenced as CD36; activation of CD36 by hexarelin in perfused hearts produced a dose-dependent change in coronary perfusion pressure that was absent in CD36-null mice. This dual receptor activity—GHS-R1a in the pituitary and CD36 in the vasculature—underlies much of the research interest in hexarelin outside of GH biology.
Published Research Overview
Hexarelin has been examined across a range of experimental systems, with a notably large body of work on cardiac tissue:
- The 2002 Circulation Research study by Bodart and colleagues identified CD36 as the receptor mediating the cardiovascular actions of hexarelin in the heart, reframing it as a molecular probe for CD36 biology.
- A study in Endocrinology (2000) reported that hexarelin improved cardiac function in rats after experimental myocardial infarction, with the effect observed at doses that distinguish it from a purely GH-mediated response.
- A 2014 study in Peptides found that a single oral dose of hexarelin was associated with preserved chronic cardiac function in a mouse myocardial infarction model, alongside shifts in autonomic nervous activity.
- Work in the International Heart Journal (2017) reported that hexarelin protected rat cardiomyocytes from in vivo ischemia/reperfusion injury, with data implicating the interleukin-1 signaling pathway downstream of cardiac GHS-R1a.
- A 2019 study in the Turkish Journal of Medical Sciences reported that hexarelin modulated PTEN expression and the Akt/mTOR axis in a rat coronary artery ligation model of heart failure, offering mechanistic context for its effects on myocardial remodeling and oxidative stress markers.
- In human research subjects, a study in Psychoneuroendocrinology (2004) found that repetitive administration of hexarelin altered sleep architecture and was accompanied by increased nocturnal secretion of GH, ACTH, cortisol, and prolactin, illustrating that its endocrine effects extend beyond GH alone.
How Does Hexarelin Differ From Other Secretagogues?
Hexarelin differs from GHRH analogues such as sermorelin, tesamorelin, and CJC-1295 because it acts through GHS-R1a rather than the GHRH receptor. Compared with its parent compound GHRP-6, hexarelin carries a 2-methyl modification that reported studies associate with substantially higher GHS-R1a binding affinity. Relative to ipamorelin—a later, highly selective GHS-R1a agonist with minimal effect on other hormones—hexarelin is less selective: in human research it has been associated with release of ACTH, cortisol, and prolactin alongside GH. Its additional binding to CD36 further separates it from newer, GH-focused secretagogues and is precisely why it remains valuable as a laboratory probe for cardiovascular and scavenger-receptor pathways.
Storage & Handling
Dynamite Research Peptides supplies hexarelin in lyophilized (freeze-dried) form. Store the powder at -20°C or below, protected from light and moisture. Reconstitute immediately before use with a sterile solvent as indicated on the Certificate of Analysis (COA), and avoid repeated freeze-thaw cycles, which can degrade peptide integrity. Handle with appropriate personal protective equipment in a well-ventilated laboratory area.
Conclusion
Hexarelin is a well-characterized research secretagogue valuable for studying GH regulation, ghrelin-receptor signaling, and—uniquely among the common GHRPs—CD36-mediated cardiovascular pathways. Its dual receptor activity makes it a versatile probe in laboratory investigations of endocrine and cardioprotective mechanisms. Our hexarelin is high-purity, third-party tested, and ships with a COA so experimental results stay reliable and reproducible.
Frequently Asked Questions
What receptor does hexarelin act on?
Hexarelin is an agonist at the growth hormone secretagogue receptor GHS-R1a, the same receptor targeted by the endogenous hormone ghrelin. It also binds the scavenger receptor CD36, which mediates several of its cardiovascular effects observed in research models.
How is hexarelin different from GHRP-6?
Hexarelin is a structural analogue of GHRP-6 carrying a 2-methyl group on its D-tryptophan residue. Reported studies associate this modification with greater metabolic stability and higher GHS-R1a binding affinity, though both peptides act on the same receptor.
What is the purity level of Dynamite Research Peptides' hexarelin?
Our hexarelin is typically 99%+ pure, verified by HPLC analysis. Detailed purity data is provided on the Certificate of Analysis (COA) included with each product.
What research applications is hexarelin used for?
It is used in laboratory studies of growth hormone regulation, ghrelin-receptor and CD36 signaling, myocardial ischemia/reperfusion, and cardioprotective mechanisms in cell and animal models.
All products are for research use only — not for human or animal consumption.