Hexarelin

Technical data

INN name

Hexarelin

Development code

EP-23905

CAS

140703-51-1

Molecular formula

C47H58N12O6

Molecular weight

887.06 g/mol

Identity and composition

Hexarelin is a synthetic hexapeptide of the growth hormone-releasing peptide class (GHRPs), studied in research as a GH secretagogue and for its direct cardiovascular action. It is an experimental compound not approved for clinical use; it is offered solely as a **product for research use.

Chemical identity data reported in the consulted literature:.

• Name: Hexarelin (Hexarelin)
• CAS number: 140703-51-1
• Molecular formula: C47H58N12O6
• Molecular weight: ~887 g/mol (approximate value; it comes from supplier sources and was not verified in a peer-reviewed primary source within this search)
• Sequence: His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2 (synthetic hexapeptide, C-terminal amidated)
• Synonyms: Examorelin, EP-23905, MF-6003, Hexarelin acetate

This presentation corresponds to a vial of 5 mg of lyophilized peptide.

Mechanism of action

Hexarelin acts primarily as agonist of the GH secretagogue receptor type 1a (GHS-R1a) in the pituitary and hypothalamus, partially mimicking the action of ghrelin. Activation of this receptor operates through a phospholipase C-dependent pathway, with production of IP3 and an increase in intracellular calcium, which promotes the exocytosis of growth hormone. Its GH-releasing effect is described as complementary and synergistic with that of GHRH, which acts through a cAMP-dependent pathway (PMID 15361691).

Independently of GHS-R1a, in experimental models hexarelin has been identified to bind to CD36, a cardiac receptor proposed as a mediator of cardioprotective effects (PMID 25278975; PMID 15176951).

In addition, it has been observed that chronic administration down-regulates the expression of GHS-R1a mRNA at the pituitary and hypothalamic level (PMID 15361691).

Pharmacokinetics

The secondary literature reports a half-life of approximately 75 minutes to 2 hours. It is important to note that this datum comes from secondary/commercial sources and was not confirmed in a peer-reviewed primary source within this search, so it should be taken as indicative.

In the secretagogue literature, activity is described via routes parenteral, intranasal, and with some oral activity. No additional pharmacokinetic parameters (exact bioavailability, clearance, volume of distribution) are available in the consulted literature, so they are not asserted here.

Scientific evidence

The available evidence is preliminary and early-phase. Hexarelin is a research compound that is neither approved nor commercialized. It is reported to have reached phase II clinical trials for GH deficiency (including its use as a diagnostic agent of GH reserve) and for cardiac indications/congestive heart failure, but development was discontinued (the exact phase and the status of the trials are reported by secondary sources and a specific NCT registration was not confirmed).

La cardioprotective activity —such as the attenuation of cardiac fibrosis and protection against ischemia/reperfusion— is documented mainly in animal models (rat) and has not been established in humans (PMID 22842067; PMID 25278975).

In summary: it should be considered a compound experimental, with limited clinical evidence in humans. The preclinical evidence suggests research directions, not applicable or promised results.

Research applications

Product for research use.

It is described as potentially suitable for research lines in a controlled environment, such as:

• Studies in vitro e in vivo (animal models) on the GH secretagogue pathway and the GHS-R1a receptor.
• Experimental research on CD36 signaling and the cardiovascular effects described in animal models.
• Comparative studies within the GHRP class.

Not applicable for:

• clinical use, therapeutic use, or diagnostic or clinical use of any kind.
• Use as a supplement, medication, or performance-enhancing product.

There is no established regulatory safety profile or approval for clinical use.

Research protocols

The literature reviewed does not provide specific dosing protocols or concentrations used in studies for hexarelin, so no figures are given here to avoid unsupported claims.

What is documented is that the chronic administration was associated, in experimental models, with attenuation of cardiac fibrosis (PMID 22842067) and with the down-regulation of GHS-R1a mRNA (PMID 15361691). These findings describe repeated-administration regimens in animal research, without this constituting a transferable guideline.

Any experimental design must be based on the corresponding primary literature and on the good practices of the responsible laboratory.

Reconstitution

General standard laboratory guide (not a clinical use instruction):

• The lyophilized peptide is usually reconstituted with bacteriostatic water (water for injection with 0.9% benzyl alcohol) or, depending on the protocol, with sterile water for injection.
• It is recommended to add the diluent letting it run slowly down the wall of the vial, avoiding directing the stream directly onto the powder.
• Do not shake vigorously; the vial should be swirled gently until complete dissolution.
• The diluent volume is chosen according to the working concentration desired for the 5 mg in the vial.
• Handle under aseptic conditions.

Stability and storage

Recommended standard management:

• Lyophilized (unreconstituted): store protected from light and moisture. For prolonged storage, freezing is recommended (typically -20 °C or below); in the short term it can be kept refrigerated. - Reconstituted: store refrigerated (2–8 °C) and use within a short period, according to laboratory practice; avoid repeated freeze/thaw cycles. - Avoid exposure to elevated temperatures and direct light.

These are general peptide-handling guidelines; the literature consulted does not specify stability data proper to hexarelin.

Safety profile

The human safety data are limited due to incomplete clinical development; there is no established regulatory safety profile and the compound is not approved for clinical use.

Documented considerations for the GH secretagogue class:

• As a GH secretagogue, it can induce acute GH release. - For the GHRPs, described are concomitant elevations of cortisol and prolactin; this point was not specifically confirmed for hexarelin in this search and should be taken with caution. - The chronic administration is associated with desensitization/down-regulation of GHS-R1a (PMID 15361691).

No formal clinical contraindications are available in the literature consulted. We reiterate: for research use only, not for clinical use.

Comparative context

Hexarelin belongs to the class of GH-releasing peptides (GHRPs), along with GHRP-6, GHRP-2, and endogenous ghrelin.

• Compared with ghrelin: ghrelin is the endogenous ligand of GHS-R1a and shows marked orexigenic effects. Hexarelin, in contrast, stands out for its additional affinity for CD36, which in experimental models mediates direct cardiac effects (PMID 25278975).
• Comparative cardiac role: comparative studies suggest that ghrelin would play a minor role in the physiological control of cardiac function in the rat compared to the activity of hexarelin via CD36.

In summary, within its class hexarelin stands out by combining GHS-R1a agonism with CD36 signaling.

History and development

Hexarelin (synonyms: Examorelin, EP-23905, MF-6003) is a synthetic hexapeptide developed as a growth hormone secretagogue. According to the literature consulted, it reached phase II clinical trials, both for GH deficiency —including its use as a diagnostic agent of GH reserve— and for cardiac indications/congestive heart failure. However, its development was discontinued and it did not come to be approved or marketed. The exact phase and status of the trials come from secondary sources and a specific NCT registration was not confirmed. Much of the subsequent research interest focused on its cardiovascular action through CD36, documented in animal models.

FAQ

Certificate of analysis per batch

Hexarelin batches with certificate of analysis published in the COA catalog:

• Lot EXO010626142A — 5 mg, issued 2026-05-29
• Lot EXO010626142B — 2 mg, issued 2026-05-29

Scientific references (4)

Peer-reviewed literature on Hexarelin, with its PubMed identifier where available:

• Short term effect of intranasal administration of hexarelin--a synthetic growth hormone-releasing peptide. Preliminary communication (Frenkel J et al. · Journal of pediatric endocrinology & metabolism: JPEM · 1995) PMID 7584696.
• GH-releasing activity of Hexarelin, a new growth hormone releasing peptide, in infant and adult rats (Deghenghi, et al. · Life Sciences · 1994) PMID 7910650.
• Growth hormone-releasing activity of hexarelin in humans. A dose-response study (Imbimbo, et al. · European Journal of Clinical Pharmacology · 1994) PMID 7957536.
• Identification of a pituitary growth hormone-releasing peptide (GHRP) receptor subtype by photoaffinity labeling (Ong, et al. · Endocrinology · 1998) PMID 9421445.

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