What is hexarelin?
Hexarelin is a synthetic growth hormone-releasing peptide (GHRP), a six-residue chain that makes the pituitary release growth hormone (GH). A 1994 rat study describes it as a GHRP analog in which tryptophan was replaced by the chemically more stable 2-methyl-tryptophan (Deghenghi et al., 1994), and a 1997 human study calls it a super-analog of GHRP-6 (Arvat et al., 1997).
It acts at the growth hormone secretagogue receptor, GHS-R1a, the receptor for ghrelin (Orkin et al., 2003), and also binds CD36, which its coronary effect in perfused hearts requires (Bodart et al., 2002). A 2018 review reported that the GHRPs it discussed, hexarelin among them, were not FDA approved (Sigalos et al., 2018), and the 2026 WADA Prohibited List names it among prohibited GH-releasing peptides. Disguised Alpha supplies it, listed as Hexarelin Acetate, as a 5MG lyophilized vial for laboratory research use only. Nothing on this page is guidance for use in people.
Hexarelin reference data
| Property | Value |
|---|---|
| Name | Hexarelin (listed as Hexarelin Acetate) |
| Also called | Examorelin (INN), EP-23905, MF-6003 |
| Sequence | His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2 (L-histidyl-2-methyl-D-tryptophyl-L-alanyl-L-tryptophyl-D-phenylalanyl-L-lysinamide): a linear hexapeptide with two D-amino acids, a non-standard 2-methyl-tryptophan and an amidated C-terminus |
| Compound class | Growth hormone secretagogue of the GHRP family; ghrelin receptor (GHS-R1a) agonist that also binds CD36 |
| Molecular formula | C₄₇H₅₈N₁₂O₆ (free peptide) |
| Molecular weight | 887.04 g/mol (free peptide) |
| PubChem CID | 6918297 |
| Form | Lyophilized powder, 5MG per vial, as listed on the product page |
| Testing | Every order ships with certificate access for its lot, per the product page |
Format, strength, formula, weight and storage are from the product page. Its formula and 887.04 g/mol describe the free peptide and match PubChem CID 6918297 (887.0 g/mol), the source of the aliases and sequence. PubChem records the 1:1 acetate salt as C₄₉H₆₂N₁₂O₈, 947.1 g/mol (CID 88325556).
See it beside the other compounds on this site in the peptide molecular weight reference table.
What the research covers
Published work on hexarelin falls into five areas; each summary names its model. Of roughly 300 PubMed records (October 2026), those tagged as clinical trials all date from 1994 to 2004.
Origin and GH release in rats
In conscious 10-day-old rats, hexarelin strongly stimulated GH secretion. In anesthetized adult male rats, intravenous hexarelin and GHRP-6 released GH with peaks within 10 minutes and similar effectiveness at every amount tested, and subcutaneous hexarelin gave a long-lasting release slightly larger than GHRP-6 (Deghenghi et al., 1994).
In a follow-up, 3 to 10 days of repeated hexarelin enhanced later GH responses in pups but not in adult rats, and in vitro its effect was transient. The authors proposed a minor direct pituitary action, GHRH release in adult rats, and an unknown hypothalamic factor acting together with GHRH (Torsello et al., 1996). Models: infant and adult rats.
Two binding sites: GHS-R1a and CD36
Merck scientists found a high-affinity site in pig and rat anterior pituitary membranes shared by hexarelin, GHRP-6 and two non-peptides, MK-0677 and L-692,429. Binding affinity tracked GH-releasing activity, and GHRH and somatostatin did not displace it (Pong et al., 1996). In human hypothalamic and pituitary membranes, radioiodinated Tyr-Ala-hexarelin bound with nanomolar affinity and was displaced by hexarelin, GHRP-2, GHRP-6 and MK-0677 (Muccioli et al., 1998).
In the heart, photoaffinity labeling found an 84 kDa protein whose N-terminal sequence matched CD36, a glycoprotein on cardiomyocytes and microvascular endothelial cells. Hexarelin raised coronary perfusion pressure in perfused hearts, but not in hearts from CD36-null mice or from spontaneously hypertensive rats lacking CD36 (Bodart et al., 2002). Cross-linking placed the binding site within CD36 residues Asn132 to Glu177, a region overlapping the binding domain for oxidized LDL (Demers et al., 2004). Models: pig, rat and human membranes, perfused rat and mouse hearts.
Hormone release in human studies
In 12 healthy young volunteers, hexarelin released GH by the intravenous, subcutaneous, intranasal and oral routes. The intravenous response was about twice that to the same amount of GHRH, and bioavailability estimated from the GH response was about 77% subcutaneous, 5% intranasal and 0.3% oral (Ghigo et al., 1994).
In six young adults, hexarelin and GHRP-2 gave similar, strong GH responses, larger than after GHRH, and both raised prolactin, ACTH and cortisol, the last two about as much as human corticotropin-releasing hormone did. The authors called both peptides not fully specific (Arvat et al., 1997). Models: healthy young adults.
Desensitization with repeated exposure
In Chinese hamster ovary cells expressing human GHS-R1a, hexarelin raised intracellular calcium, and the response was markedly desensitized 2 to 5 minutes after a first exposure (Orkin et al., 2003). In conscious male rats, a second bolus 2 hours after the first released significantly less GH, though a third did not differ significantly from the first. During continuous infusions of 6 to 174 hours, GH peaked within 40 minutes and returned to basal levels, pulsatile release matched saline controls, and only the longest infusion raised IGF-I (Conley et al., 1998).
In healthy elderly volunteers who received repeated hexarelin for 16 weeks, the GH response to a test exposure fell to about 55% of baseline and returned to baseline 4 weeks after the course ended, while serum IGF-I did not change significantly. The authors called the attenuation partial and reversible (Rahim et al., 1998). Models: transfected cells, rats, healthy elderly volunteers.
Heart models
In hypophysectomized rats, 7 days of hexarelin prevented the worsening of ischemia-reperfusion damage in their explanted hearts, including rises in end-diastolic pressure, coronary perfusion pressure and creatine kinase release. GH did the same, while EP 51389, a GHRP that does not bind the heart, did not (Locatelli et al., 1999). In male ghrelin-knockout mice after coronary artery ligation, 2 weeks of hexarelin or ghrelin lowered mortality (6.7% and 14.3%, against 50% with vehicle), and hexarelin outdid ghrelin on ejection fraction (Mao et al., 2013).
In people, hexarelin raised left ventricular ejection fraction in seven men with GH deficiency, who released almost no GH, and in nine control men, without changes in blood pressure, catecholamines or cardiac output. The authors read the short-lasting effect as probably independent of GH (Bisi et al., 1999). Models: rat hearts, mice, adult men.
Key studies
- Deghenghi R, et al. "GH-releasing activity of Hexarelin, a new growth hormone releasing peptide, in infant and adult rats." Life Sci. 1994. PMID 7910650. DOI 10.1016/0024-3205(94)00510-9. Infant and adult rats, compared with GHRP-6.
- Ghigo E, et al. "Growth hormone-releasing activity of hexarelin, a new synthetic hexapeptide, after intravenous, subcutaneous, intranasal, and oral administration in man." J Clin Endocrinol Metab. 1994. PMID 8126144. DOI 10.1210/jcem.78.3.8126144. Healthy young volunteers, four routes.
- Arvat E, et al. "Effects of GHRP-2 and hexarelin, two synthetic GH-releasing peptides, on GH, prolactin, ACTH and cortisol levels in man. Comparison with the effects of GHRH, TRH and hCRH." Peptides. 1997. PMID 9285939. DOI 10.1016/s0196-9781(97)00016-8. Healthy adults, hormone specificity.
- Rahim A, et al. "Growth hormone status during long-term hexarelin therapy." J Clin Endocrinol Metab. 1998. PMID 9589671. DOI 10.1210/jcem.83.5.4812. Healthy elderly volunteers over 16 weeks, desensitization.
- Locatelli V, et al. "Growth hormone-independent cardioprotective effects of hexarelin in the rat." Endocrinology. 1999. PMID 10465272. DOI 10.1210/endo.140.9.6948. Hypophysectomized rats, explanted hearts.
- Bodart V, et al. "CD36 mediates the cardiovascular action of growth hormone-releasing peptides in the heart." Circ Res. 2002. PMID 11988484. DOI 10.1161/01.res.0000016164.02525.b4. Rat cardiac membranes, CD36-null mouse hearts.
Handling and storage of hexarelin vials
General laboratory practice for this lyophilized peptide, consistent with the product page's storage card, the peptide storage guide and the reconstitution guide:
- Store the sealed vial at -20°C, protected from light; the product page calls the lyophilized powder the most stable form. Let a cold vial reach room temperature before opening so moisture does not condense on the cake.
- Use the diluent the protocol names. Hexarelin is a basic peptide (histidine, lysine and a free amino terminus, no acidic residues), and the reconstitution guide notes that basic peptides dissolve best in acidic solutions. Swirl rather than shake.
- After reconstitution, refrigerate at 2 to 8°C, protected from light, and avoid freeze/thaw cycles, as the product page lists.
- Light protection matters because hexarelin carries tryptophan and 2-methyl-tryptophan, and the storage guide lists tryptophan among residues prone to oxidation and photo-oxidation.
- Record the lot number with its certificate, and check identity against C₄₇H₅₈N₁₂O₆ and a monoisotopic mass of 886.46 Da (PubChem CID 6918297).
Frequently asked questions
What is hexarelin?
A synthetic GH-releasing hexapeptide, also called examorelin, with the sequence His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2 (Deghenghi et al., 1994). It acts at the ghrelin receptor, GHS-R1a, and also binds CD36 in the heart (Bodart et al., 2002).
Is hexarelin a peptide?
Yes. The hexarelin peptide is a linear chain of six amino acids with an amidated C-terminus, including two D-amino acids and a non-standard 2-methyl-tryptophan (PubChem CID 6918297). MK-0677 (MK-677), which binds the same pituitary site, is a non-peptide (Pong et al., 1996).
Is hexarelin selective for growth hormone?
No. In healthy young adults it also raised prolactin, ACTH and cortisol (Arvat et al., 1997). In a separate swine study that did not include hexarelin, GHRP-6 and GHRP-2 raised ACTH and cortisol, but ipamorelin did not beyond the levels seen after GHRH (Raun et al., 1998).
Does the response to hexarelin fade with repeated exposure?
Partly and reversibly. In healthy elderly volunteers exposed for 16 weeks, the GH response fell to about 55% of baseline and was back at baseline 4 weeks after stopping (Rahim et al., 1998).
Is hexarelin approved, and is it banned in sport?
A 2018 review reported that the GHRPs it covered, hexarelin among them, were not FDA approved (Sigalos et al., 2018). The 2026 WADA Prohibited List names examorelin (hexarelin) among the GH-releasing peptides under S2.2.4, growth hormone releasing factors, in class S2, which is prohibited at all times.
Where can researchers buy hexarelin?
Disguised Alpha lists it as Hexarelin Acetate, a 5MG lyophilized vial, for laboratory research use only: Hexarelin Acetate.
Related compounds and guides
- Hexarelin Acetate 5MG
- Ipamorelin research guide
- MK-677 (ibutamoren) research guide
- Growth hormone secretagogues guide
- Peptide storage guide
- How to reconstitute peptides in the lab
- What is a peptide?
This product is for research use only. It has not been evaluated for safety or effectiveness in humans. Not for human consumption. All products are intended for laboratory research purposes only.