Hexarelin Acetate Research Peptide

Hexarelin is a synthetic six-residue peptide, His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2, from the growth hormone-releasing peptide family. It acts on the ghrelin receptor and also binds CD36, a scavenger receptor. In laboratory research it is used mainly in heart and macrophage models, as well as in ghrelin receptor pharmacology.

Examorelin is its International Nonproprietary Name, the official generic name used in regulatory and clinical documents. Hexarelin is the original name, reflecting its six residues. EP-23905 and MF-6003 are development codes used in early studies. All of these names refer to the same peptide, and papers indexed under any of them belong to the same body of work.

By one methyl group. GHRP-6 has D-tryptophan at position two; hexarelin has D-2-methyl-tryptophan, which the 1994 paper describes as chemically more stable. In rats the two gave similar growth hormone responses into a vein, while hexarelin under the skin was longer-lasting. The CD36 heart work was carried out with hexarelin and its derivatives.

Sermorelin, Tesamorelin and CJC-1295 are GHRH analogues acting on the GHRH receptor. GHRP-2, GHRP-6 and Ipamorelin act on the ghrelin receptor, as hexarelin does. Hexarelin is the one chosen when a study concerns CD36, because it is the ligand that site was discovered with, and because its heart and macrophage work does not depend on the pituitary at all.

CD36 is a glycoprotein on the surface of many cell types, including heart muscle cells, the endothelial cells lining small blood vessels, and macrophages. It is called a scavenger receptor because it takes up modified fats such as oxidised LDL, and it also helps cells take in fatty acids. Its role in heart energy use and atherosclerosis makes it a widely studied target.

No. In the 1999 binding study, MK-0677 and EP 51389, both potent growth hormone secretagogues, did not compete for the cardiac site. In the other direction, the Montreal group later developed EP 80317, a related peptide that binds CD36 but has no growth hormone-releasing activity, so the two activities can be separated.

Yes. The ghrelin receptor, GHS-R1a, is the receptor through which growth hormone-releasing peptides release growth hormone from the pituitary. A 2006 macrophage study found that hexarelin’s effects on cholesterol transporters involved binding to both CD36 and GHS-R1a, so it is studied as a ligand with two distinct receptor targets.

They removed growth hormone from the picture. In hypophysectomised rats, which cannot make growth hormone, hexarelin still limited ischaemia-reperfusion damage in explanted hearts, while EP 51389, a secretagogue that does not bind the heart, did not. Later, hexarelin’s effect on coronary pressure was absent in hearts lacking CD36.

In perfused hearts from normal animals, hexarelin raised coronary perfusion pressure in a dose-dependent way. In hearts from CD36-null mice, and from spontaneously hypertensive rats that naturally lack CD36, that response was missing. The strength of the response also matched how much CD36 each heart expressed, linking the effect to CD36.

In ghrelin-knockout mice given equal molar amounts after coronary artery ligation, both peptides lowered two-week mortality compared with vehicle, at 6.7% for hexarelin and 14.3% for ghrelin against 50%. Hexarelin gave better ejection fraction and pressure measures than ghrelin, and both reduced sympathetic nervous activity.

In cultured THP-1 macrophages it increased the cholesterol transporters ABCA1 and ABCG1 and cholesterol outflow through a PPAR-gamma-dependent pathway. In apolipoprotein E-null mice on a lipid-rich diet, it reduced atherosclerotic lesions. The binding site on CD36 overlaps the region that takes up oxidised LDL.

Hexarelin is not a controlled drug under the Misuse of Drugs Act 1971; growth hormone itself appears on the Class C list, but growth hormone-releasing peptides such as hexarelin do not. It is not a licensed medicine in the UK. It is sold in the UK as a research compound for laboratory use only, which is how Crown Peptides supplies it. This is general information, not legal advice.

Hexarelin Acetate is coming soon to Crown Peptides in 5mg vials, available singly or in packs of 3, 5 or 10 with a saving on every vial. Orders ship from the UK, and every batch is independently tested, with its Certificate of Analysis published on this page once stock arrives.

Five milligrams of an 887-dalton peptide is roughly 5.6 micromoles, or about 5.3 micromoles if calculated on the monoacetate salt; the exact peptide content is on the batch’s Certificate of Analysis. The cardiac binding site was measured at a dissociation constant of about 14.5 nanomolar, so one vial covers a good deal of membrane and cell work.

Keep the unreconstituted powder at -20°C ± 5°C, dry and away from light. The sequence contains two tryptophan residues, one of them methylated, and tryptophan is sensitive to light and oxidation, so vials are best kept sealed and dark until use. Prepared solutions should follow storage conditions validated for your study design, and each batch’s Certificate of Analysis documents the material as dispatched.