Hexarelin · Research brief

Hexarelin Peptide: Research Overview, Purity Data and Where to Buy

Real Peptides Research TeamEditorial

Updated October 14, 202611 min read

58 WORDS

Short answer

Hexarelin is one of the few growth hormone secretagogues in the published literature that doesn't act through a single receptor. Alongside activity at the ghrelin receptor, research describes binding at CD36, a scavenger receptor expressed densely in cardiac and vascular tissue, which is why a large share of Hexarelin papers sit in cardiovascular journals rather than endocrinology ones.

Key takeaways

Hexarelin is a synthetic hexapeptide growth hormone secretagogue, also known as examorelin, with CAS number 140703-51-1 and a molecular weight of approximately 887 g/mol.
Published research describes two receptor targets for Hexarelin: the ghrelin receptor GHS-R1a and the scavenger receptor CD36, which is why much of its literature is cardiovascular rather than endocrine.
HPLC purity and net peptide content measure different things, and comparing one supplier's purity figure against another's content figure produces a false equivalence.
Lyophilized Hexarelin is typically held at or below -20°C, desiccated and protected from light, with repeated freeze-thaw cycling being a greater degradation risk than brief ambient transit excursions.
Hexarelin is not an FDA-approved drug and appears on the World Anti-Doping Agency S2 prohibited list covering growth hormone secretagogues.
Real Peptides publishes per-lot certificates of analysis openly rather than on request, so a specific Hexarelin batch can be verified against its own chromatogram and mass spectrum.

Our team supplies Hexarelin to independent laboratories and academic research groups, and the questions we field most often have nothing to do with mechanism. They're about lot traceability, molecular identity confirmation, and cold chain integrity. All products are sold for laboratory research use only and are not for human consumption.

What is Hexarelin?

Hexarelin, also catalogued as examorelin, is a synthetic hexapeptide growth hormone secretagogue with the sequence His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2 and a molecular weight of roughly 887 g/mol. The literature describes it as a GHS-R1a agonist that also binds the scavenger receptor CD36. It ships as a lyophilized powder for laboratory research.

The common oversimplification is that Hexarelin is just a stronger version of the earlier growth hormone-releasing peptides. Receptor potency is only part of the picture, because the CD36 interaction gives Hexarelin a pharmacological footprint the older secretagogues don't fully share, and reports of receptor desensitization during repeated exposure complicate head-to-head comparisons further. This page covers the compound's class and mechanism, what published studies actually examine, laboratory handling and storage, how purity is verified per lot, regulatory status, and how researchers source it.

A hexapeptide built to survive enzymatic breakdown

Hexarelin is a synthetic six-amino-acid peptide, which is exactly where the name comes from. Its structure, His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2, carries two unnatural D-configuration residues and a methyl group on the tryptophan at position two, plus an amidated C-terminus. Those modifications aren't cosmetic. They're what slow enzymatic degradation relative to the native receptor ligand, and they're the reason the molecule shows a usable half-life in the animal models where it's been characterized.

The primary target described in the literature is the growth hormone secretagogue receptor type 1a (GHS-R1a), a G protein-coupled receptor expressed in the hypothalamus and on pituitary somatotrophs. Agonism at GHS-R1a triggers a phospholipase C and inositol trisphosphate signalling cascade, raising intracellular calcium and driving growth hormone release in a pulsatile pattern rather than a flat elevation. Research also describes suppression of somatostatin tone, which is the inhibitory brake on that pulse.

The second target is where Hexarelin separates from the pack. CD36, sometimes called fatty acid translocase, is a class B scavenger receptor expressed in cardiomyocytes, macrophages and vascular endothelium. Studies report that several cardiovascular effects of Hexarelin persist in models lacking a functional GHS-R1a pathway, pointing to CD36 as an independent route of action.

Hexarelin is also described as less receptor-selective than Ipamorelin. The literature reports concurrent elevation of other pituitary hormones in some experimental settings, which matters when a study design calls for an isolated growth hormone signal. Our team has worked with researchers who switched secretagogues mid-study purely on that selectivity point.

What the published literature on this compound actually examines

The Hexarelin research record splits into three broad streams, and only one of them is endocrine. Searching the indexed literature for Hexarelin growth hormone secretagogue studies returns decades of work on pituitary signalling, somatotroph responsiveness and comparative potency against other secretagogue peptides.

The second stream is cardiovascular, and it's larger than most people expect. Work indexed under Hexarelin and cardioprotection examines ischemia-reperfusion models, ventricular function and cardiac remodelling, with several reports describing effects that appear independent of circulating growth hormone concentrations. The mechanistic bridge there is the receptor work catalogued under Hexarelin and CD36, which links the peptide to a receptor with established roles in fatty acid uptake and inflammatory signalling.

The third stream is the one researchers most often overlook. Studies report attenuation of the growth hormone response with repeated exposure, a desensitization pattern catalogued in the literature on growth hormone secretagogue receptor desensitization. That finding shapes experimental design more than any potency figure does, because a study measuring response magnitude over an extended timeline is measuring a moving target.

A practical caution on reading this body of work: much of the foundational Hexarelin literature dates from the 1990s, when it was investigated as a clinical candidate. Methods, assay sensitivity and reporting standards from that era don't always map cleanly onto current practice, and the hedged language in those abstracts is there for a reason. The information here is educational and describes published research findings, not guidance for any use outside a controlled laboratory setting.

Laboratory handling, storage and stability basics

Hexarelin arrives as a lyophilized (freeze-dried) powder, and in that state it's far more forgiving than most people assume. Research-grade lyophilized peptides are typically held at or below -20°C for long-term storage, protected from light, and kept desiccated, because residual moisture is the single biggest driver of degradation in a sealed vial. Short ambient excursions during transit are normal for lyophilized material and are not the failure point most procurement teams worry about.

The failure points that matter are different. Repeated freeze-thaw cycling fragments peptide chains, so laboratories working through a lot over weeks generally pull it from cold storage as few times as possible. Humidity ingress after a stopper has been punctured is a second one. Light exposure is a third, which is why amber vials and opaque secondary packaging exist.

Once a Hexarelin lot is in solution, stability drops sharply and the material becomes a cold chain item in the strict sense, with refrigerated handling and a short usable window. Peptide bonds hydrolyse in aqueous environments, and the tryptophan residues in the Hexarelin sequence are specifically susceptible to oxidation. Appearance tells you nothing here. A degraded solution can look identical to an intact one.

Real Peptides doesn't publish preparation instructions, and that's deliberate rather than an oversight. These are research-use-only compounds, so the only preparation-adjacent figure we supply is the mass of peptide stated on the certificate for that lot, which is the single input a laboratory needs for its own milligram-per-millilitre concentration arithmetic. Everything downstream of that number is the receiving laboratory's protocol decision.

How purity is verified before a lot ships

Purity verification for Hexarelin rests on two instruments doing two different jobs. Reverse-phase high-performance liquid chromatography (RP-HPLC) separates the target peptide from truncated sequences, deletion products and synthesis by-products, reporting the target as a percentage of total peak area. Mass spectrometry, usually electrospray ionisation or MALDI-TOF, confirms molecular identity by matching the observed mass against the theoretical mass of roughly 887 g/mol for the Hexarelin sequence. Chromatography answers how clean. Mass spectrometry answers whether it's the right molecule at all.

Here's the distinction almost nobody checks, and it's the one that causes the most confusion in procurement. HPLC purity and net peptide content are not the same measurement. HPLC purity describes the proportion of peptide material that is the correct sequence. Net peptide content describes how much of the vial's total mass is peptide at all, with the balance being counter-ions such as residual trifluoroacetic acid, bound water and salts. A lot can report high chromatographic purity while a meaningful fraction of the gross weight isn't peptide. Comparing one supplier's purity figure against another's content figure is an apples-to-oranges error, and we see it constantly.

This is why per-lot documentation beats a blanket specification sheet. A generic claim applies to a product line. A certificate of analysis applies to the specific vial in a researcher's freezer, with a lot number that ties chromatogram and spectrum to that batch. Real Peptides publishes certificates openly at realpeptides.co/coas, so a Hexarelin lot can be verified against its own analytical data rather than a marketing number.

Regulatory status and ordering Hexarelin for laboratory use

Hexarelin is not an FDA-approved drug product. It has no approved indication, it isn't a dietary supplement ingredient, and it's sold strictly as a research chemical for in vitro and laboratory investigation. Anyone describing Hexarelin as a therapy is misrepresenting its regulatory position. The World Anti-Doping Agency lists growth hormone secretagogues, Hexarelin among them, under its S2 category of prohibited substances, banned both in and out of competition.

For procurement, the verification checklist is short and worth running before any order. Confirm the CAS registry number, 140703-51-1, matches the supplier's listing. Confirm the stated molecular weight is consistent with the Hexarelin sequence. Confirm a lot-specific certificate exists and is publicly viewable rather than available on request. Confirm the supplier states research-use-only terms plainly instead of burying them in a footer.

Real Peptides manufactures in small batches with exact amino-acid sequencing and third-party analytical testing, which is a quality control model rather than a marketing posture. Small-batch synthesis means fewer vials share a single analytical record, so a certificate represents a tighter population of material. Researchers sourcing this compound can review the Hexarelin product page for the current lot's specifications, browse the wider research peptide catalog for related secretagogue and signalling compounds, or read how we define analytical standards across the line at pure peptides.

Hexarelin compared with other growth hormone secretagogues in research

The table below contrasts the compounds researchers most often evaluate alongside this one, focused on receptor target and what the published work actually investigates rather than on potency rankings.

Compound	Primary receptor target in the literature	What published research focuses on	Professional assessment
Hexarelin	GHS-R1a agonist, plus documented binding at CD36	Pituitary growth hormone signalling, cardiac ischemia-reperfusion models, receptor desensitization over repeated exposure	The only secretagogue in this group with a substantial cardiovascular literature driven by a second, non-ghrelin receptor pathway
Ipamorelin	GHS-R1a agonist, described as highly selective	Isolated growth hormone release with minimal effect on other pituitary hormones in reported models	Preferred where a study design requires a clean growth hormone signal without confounding hormone movement
GHRP-6	GHS-R1a agonist, earliest-generation secretagogue peptide	Foundational receptor characterisation work and appetite-related signalling in animal models	Historically important for mapping the receptor, but largely superseded in newer study designs
CJC-1295 (no DAC)	Growth hormone-releasing hormone receptor, a different receptor entirely	GHRH-pathway signalling rather than ghrelin-pathway signalling	Not a secretagogue in the same class, which makes direct comparison with Hexarelin a category error

What If: Hexarelin Sourcing and Handling Scenarios

What if a Hexarelin shipment arrives at room temperature?

Check whether the material is still a dry, intact lyophilized cake before assuming a loss. Lyophilized peptides tolerate short ambient excursions far better than solutions do, because degradation in a sealed, desiccated vial is driven primarily by moisture rather than by temperature alone. What does warrant rejection is a vial that arrives with a cracked seal, visible moisture, or a cake that has collapsed into an oily or discoloured residue.

What if the certificate of analysis has no lot number on it?

Treat it as a product specification sheet, not a certificate, and request the lot-specific document. A certificate without a lot number cannot be traced to the vial in hand, which defeats its entire purpose in a research audit trail. Genuine analytical documentation carries a batch identifier, a test date, and the actual chromatogram and mass spectrum rather than a summary line. Suppliers publishing certificates openly, as at our COA library, remove that friction entirely.

What if the observed mass doesn't match the expected molecular weight?

Stop and query the lot before it enters any experimental workflow. A mass spectrum that deviates meaningfully from the theoretical value for the Hexarelin sequence indicates either a different compound, a significant deletion sequence population, or an adduct the report hasn't accounted for. Small, predictable offsets from sodium or potassium adducts are routine and usually annotated. Unexplained deviations are not, and no purity percentage compensates for a molecular identity mismatch.

The blunt truth about research peptide purity claims

Here's the honest answer: a 99% purity claim printed on a website means nothing on its own. It isn't tied to the vial you receive, it doesn't specify whether the figure is chromatographic purity or net peptide content, and it carries no analytical evidence a reviewer could examine. The only purity data worth anything is lot-specific, dated, and published with the underlying chromatogram and spectrum attached. If a supplier can't produce that for the exact batch shipping to a laboratory, the number on the page is a marketing asset, not a quality control record. That distinction is the whole game in research peptide procurement.

Researchers evaluating this compound alongside other secretagogues can compare lot documentation across our catalog through the Hexarelin listing, the full research catalog, our published certificates of analysis, and our analytical standards at pure peptides.

What makes Hexarelin genuinely interesting as a research tool isn't its potency at the ghrelin receptor, which plenty of compounds share. It's that a single small hexapeptide reaches into two unrelated receptor systems, one endocrine and one scavenger-class, and that duality is precisely what makes clean experimental attribution so difficult. A result observed in a Hexarelin study may belong to GHS-R1a, to CD36, or to both at once, and the published work has spent thirty years trying to separate them. All products are sold for laboratory research use only and are not for human consumption.

References

Peer-reviewed sources on Hexarelin indexed in PubMed, listed for research context. Real Peptides supplies Hexarelin for laboratory research use only.

Hexarelin alleviates apoptosis on ischemic acute kidney injury via MDM2/p53 pathway. European journal of medical research, 2023. PMID 37710348. doi:10.1186/s40001-023-01318-w
Hexarelin attenuates abdominal aortic aneurysm formation by inhibiting SMC phenotype switch and inflammasome activation. Microvascular research, 2022. PMID 34856183. doi:10.1016/j.mvr.2021.104280
Hexarelin modulates lung mechanics, inflammation, and fibrosis in acute lung injury. Drug target insights, 2021. PMID 34871336. doi:10.33393/dti.2021.2347
Hexarelin Modulation of MAPK and PI3K/Akt Pathways in Neuro-2A Cells Inhibits Hydrogen Peroxide-Induced Apoptotic Toxicity. Pharmaceuticals (Basel, Switzerland), 2021. PMID 34066741. doi:10.3390/ph14050444
Using Synchrotron Radiation Imaging Techniques to Elucidate the Actions of Hexarelin in the Heart of Small Animal Models. Frontiers in physiology, 2021. PMID 35126171. doi:10.3389/fphys.2021.766818
Ghrelin receptor agonist hexarelin attenuates antinociceptive tolerance to morphine in rats. Canadian journal of physiology and pharmacology, 2021. PMID 32893668. doi:10.1139/cjpp-2020-0218
Hexarelin targets neuroinflammatory pathways to preserve cardiac morphology and function in a mouse model of myocardial ischemia-reperfusion. Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie, 2020. PMID 32403043. doi:10.1016/j.biopha.2020.110165
Hexarelin attenuates atherosclerosis via inhibiting LOX-1-NF-κB signaling pathway-mediated macrophage ox-LDL uptake in ApoE(-/-) mice. Peptides, 2019. PMID 31386895. doi:10.1016/j.peptides.2019.170122

Build a pack

Researching more than one compound?

Build a multi-vial pack and the discount applies automatically as you add vials.

Start a pack

Questions

Hexarelin is studied primarily in three areas: pituitary growth hormone signalling through the GHS-R1a receptor, cardiovascular models including ischemia-reperfusion work, and receptor pharmacology involving CD36. A notable feature of the literature is that several reported cardiovascular findings appear independent of circulating growth hormone, which is what directed researchers toward the CD36 pathway in the first place. All of this work is laboratory research, and Hexarelin has no approved therapeutic indication.

No. Hexarelin is not an FDA-approved drug product, has no approved indication, and is not a permitted dietary supplement ingredient. It is supplied strictly as a research chemical for laboratory investigation and is not for human or veterinary consumption. Any source describing it as a treatment is misrepresenting its regulatory status.

Both act at the growth hormone secretagogue receptor GHS-R1a, but the literature describes Ipamorelin as highly selective while Hexarelin is reported to influence additional pituitary hormones in some experimental settings. The larger difference is Hexarelin's documented binding at CD36, a scavenger receptor expressed in cardiac tissue, which gives it a cardiovascular research literature that Ipamorelin doesn't have. For study designs requiring an isolated growth hormone signal, selectivity is usually the deciding factor.

Hexarelin is sold to qualified researchers, laboratories and institutions for in vitro and laboratory research use only. It is not sold for personal use, human consumption or veterinary application. Purchasers are responsible for handling the material in accordance with their own institutional and local requirements.

Orders are placed through the product listing on our site, and each lot ships with its own certificate of analysis rather than a generic specification sheet. The certificate includes the HPLC chromatogram, mass spectrometry identity confirmation and the lot identifier, and certificates are published openly at realpeptides.co/coas so they can be reviewed before purchase. The certificate also states the mass of peptide in the vial, which is the figure a laboratory uses for its own concentration calculations.

Lyophilized Hexarelin is generally held at or below -20°C, kept desiccated and protected from light, since residual moisture is the main degradation driver in a sealed vial. Repeated freeze-thaw cycling is a bigger stability risk than a brief ambient excursion during shipping. Once in solution, stability falls sharply and the material requires refrigerated handling with a short usable window, because peptide bonds hydrolyse in aqueous conditions and the tryptophan residues in the sequence are oxidation-prone.

No. Because Hexarelin is a research-use-only compound, we don't publish preparation instructions or usage guidance of any kind. The only preparation-adjacent information we supply is the mass of peptide stated on the lot certificate, which a receiving laboratory can use as the input for its own milligram-per-millilitre concentration framework. Everything beyond that is a protocol decision belonging to the research institution.

HPLC purity reports what proportion of the peptide material present is the correct target sequence, separating it from truncated and deletion products. Net peptide content reports how much of the vial's total mass is peptide at all, with the remainder consisting of counter-ions such as residual trifluoroacetic acid, bound water and salts. They're different measurements, and comparing one supplier's purity figure against another's content figure is a common and misleading procurement error.

Yes. The World Anti-Doping Agency lists growth hormone secretagogues, including Hexarelin, under its S2 category of prohibited substances, banned both in and out of competition. This classification applies to athletes subject to anti-doping testing and is separate from the compound's research-use-only status as a laboratory chemical.

CD36, also called fatty acid translocase, is a class B scavenger receptor expressed in cardiomyocytes, macrophages and vascular endothelium, with established roles in fatty acid uptake and inflammatory signalling. Research indexed under Hexarelin and CD36 reports that some cardiovascular observations persist in models where the ghrelin receptor pathway isn't functional, pointing to CD36 as a separate route of action. It's the main reason Hexarelin study results can be difficult to attribute cleanly to one receptor system.

Three checks cover most of the risk. Confirm the CAS registry number 140703-51-1 and the stated molecular weight of roughly 887 g/mol match the Hexarelin sequence, confirm the mass spectrum on the certificate matches that theoretical mass without unexplained deviation, and confirm the certificate carries a lot number tying it to the specific batch received. A certificate without a lot identifier is a specification sheet, not an analytical record.

RESEARCH USE ONLY · NOT EVALUATED BY THE FDA