Hexarelin

For laboratory and in-vitro research use only. Hexarelin is not a drug, has not been evaluated by the FDA for safety or efficacy, and is not sold, labeled, or intended for human or veterinary use, administration, or consumption. Everything below describes published preclinical and historical human-subject research — none of it is guidance for personal use.

Ask any lab manager who’s compared growth-hormone-secretagogue peptides side by side, and they’ll tell you the spec sheets all start to look the same after a while: another hexapeptide, another purity claim, another “99%+ HPLC-verified” badge with no batch data behind it. Hexarelin is one of the more mechanistically interesting compounds in that category — it doesn’t just look like a research peptide catalog entry, it comes with three decades of published pharmacology behind it, including a cardioprotective signaling pathway that has nothing to do with growth hormone at all. So what does the literature actually show, why did a compound with this much human data never reach the market, and how do you make sure the vial in front of you matches the batch it claims to be from? Let’s work through it.

Picture the alternative: a supplier lists “Hexarelin 99% purity” next to a stock photo, ships a vial with no lot number printed anywhere, and goes quiet the moment you ask for a certificate of analysis tied to that specific batch. Now your comparison study has an unverified variable sitting in the freezer, and there’s no way to know if a null result is biology or a contaminated reagent. That’s not a hypothetical — it’s one of the most common complaints in peptide-research forums, and it’s exactly why this page spends as much time on documentation as it does on the pharmacology.

What Is Hexarelin?

Hexarelin — also referred to in the literature as Examorelin, and sometimes listed under the developmental code HEXA — is a synthetic hexapeptide (His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2) built as a growth hormone-releasing peptide-6 (GHRP-6) analog, with a D-2-methyl-tryptophan substitution that materially changes its receptor-binding profile compared to its parent compound.

The compound is registered under CAS number 140703-51-1, with a molecular formula of C47H58N12O6 and a molecular weight of approximately 887.0 g/mol. It is not an FDA-approved drug, not a dietary supplement, and is not currently marketed for any human indication anywhere in the world — a status that reflects its research history more than any single regulatory action, as the sections below explain.

What Current Research Says About Hexarelin

The literature on Hexarelin is unusual for a research peptide: a meaningful share of it comes from published human pharmacokinetic and endocrine studies conducted in the 1990s, not exclusively rodent models. That combination — genuine early-phase human data plus an active preclinical research pipeline that continues today — is part of why it keeps showing up in comparative secretagogue research.

Growth hormone secretagogue activity (GHS-R1a pathway)

Hexarelin was developed and characterized as a potent agonist at the growth hormone secretagogue receptor (GHS-R1a, the ghrelin receptor) on pituitary somatotrophs. Early human dose-response work established that intravenous, subcutaneous, and even intranasal administration produced measurable growth-hormone-releasing activity, with researchers directly comparing its potency to growth hormone-releasing hormone (GHRH) and to its GHRP-6 parent compound in the same subjects (Ghigo et al., dose-response study). Later work in patients with GHRH-receptor deficiency was specifically used to help localize where in the GH axis Hexarelin’s effects originate (Maheshwari et al.).

A GH-independent cardioprotective pathway

What sets Hexarelin apart mechanistically is that a meaningful share of its research is not about growth hormone at all. Preclinical models have identified a second binding site — the CD36 scavenger receptor on cardiac tissue — through which Hexarelin appears to signal independently of the GHS-R1a/GH axis. In a rat model of experimental myocardial infarction, Hexarelin administration was associated with improved left-ventricular functional measures relative to untreated controls , and a separate model of in-vivo ischemia/reperfusion injury linked Hexarelin exposure to interleukin-1-pathway signaling changes in cardiomyocytes . These remain animal-model findings — they describe a signaling pathway of research interest, not a treatment outcome in any species including humans.

Hormone-axis interactions beyond GH

Human studies have also documented that Hexarelin administration is not GH-selective: several trials recorded concurrent cortisol and prolactin elevation alongside the GH pulse, and researchers used this multi-hormone signature to study how Hexarelin’s activity compares to corticotropin-releasing hormone and to combinations of GHRH with arginine or pyridostigmine in different subject populations, including elderly subjects and short-stature pediatric cohorts (Arvat et al.).

Receptor desensitization findings

A recurring theme across the secretagogue literature — Hexarelin included — is attenuation of the GH response with continuous receptor exposure over time, sometimes described as tachyphylaxis. This is a pharmacodynamic finding relevant to how researchers design multi-week protocols and interpret longitudinal data, not an efficacy or safety claim about any use case.

Why it never advanced past early-phase human research

Despite a genuine body of 1990s-era human pharmacology data, Hexarelin was not pursued to regulatory approval or commercial development as a therapeutic. No sponsor has an active approval pathway for it today, and it is not sold as a prescription medicine, OTC product, or dietary supplement in the United States or elsewhere. That gap between “studied in humans” and “approved for use” is precisely why it sits in the research-chemical category rather than the pharmacy aisle.

Regulatory and anti-doping status

Hexarelin (listed under its INN, Examorelin) is explicitly named on the World Anti-Doping Agency’s Prohibited List, under category S2.2.4, “Growth Hormone Releasing Peptides (GHRPs)” — a category that also includes GHRP-2 and GHRP-6 (WADA S2 prohibited substances). Separately, the FDA added both GHRP-2 and GHRP-6 — the closest structural relatives to Hexarelin — to its list of bulk drug substances presenting significant safety risks for compounding purposes on September 29, 2023 (FDA 503A/503B bulk substances list). Hexarelin itself is not currently named on that specific FDA list, but it shares the same growth-hormone-secretagogue mechanism and regulatory scrutiny as the compounds that are — worth knowing before assuming “not listed” means “unregulated.”

Purity, Certificates of Analysis, and Testing Standards

A purity percentage printed on a product page is a marketing claim. A Certificate of Analysis tied to the specific lot in your freezer is data — and treating those as interchangeable is how research budgets quietly get spent on unverifiable material. A real COA for a compound like Hexarelin should show, at minimum: the batch or lot number matching your vial, HPLC-determined purity reported as a number (not just asserted as “99%+”), mass spectrometry confirming molecular weight against the expected ~887 g/mol, and a dated signature from the issuing lab. Our own COA reporting standards page walks through exactly what we test for and how to read the results. If a vendor can’t produce that before you pay, ask yourself what else they’re not showing you.

How NexaPeptideLabs Sources and Verifies Hexarelin

NexaPeptideLabs orders Hexarelin in defined production batches and requires independent third-party HPLC and mass spectrometry verification before any batch is released for sale. Each certificate is tied to its specific lot — never pooled across production runs — and it’s posted at checkout rather than gated behind a support request. If you’re comparing secretagogue peptides for a GH-axis or cardiac-signaling protocol, our GHRP-6, GHRP-2, and Ipamorelin research listings sit in the same Growth Hormone Research category and carry the same documentation standard.

Hexarelin is for sale to qualified research buyers as a lyophilized (freeze-dried) powder intended solely for laboratory and in-vitro applications. Purchasing requires acknowledgment that the material is for research use only and will not be used for human or animal administration, consistent with our research use and policies page.

Storage and Handling for Laboratory Use

Lyophilized Hexarelin should be stored at −20°C, sealed, and protected from light and moisture. Once reconstituted for in-vitro assay purposes, minimize freeze-thaw cycling, aliquot what a given experiment requires, and hold aliquots at the temperature specified on that batch’s COA — stability data is lot-dependent, so don’t assume this quarter’s batch behaves like last quarter’s. A standard chest freezer held at a steady −20°C generally preserves peptide integrity better than a frost-free unit with fluctuating internal temperatures, even though the latter looks more convenient on paper.

Frequently Asked Questions

What is Hexarelin?

It’s a synthetic hexapeptide and GHRP-6 analog, studied in preclinical and early-phase human research as a growth hormone secretagogue acting on the GHS-R1a (ghrelin) receptor.

What has Hexarelin been studied for in research?

Published literature has investigated it for GH-axis secretagogue activity, GH-independent cardioprotective signaling via the CD36 receptor, and comparative endocrine research involving cortisol and prolactin co-release. These are research findings, not evidence of effects in any clinical use case.

Is Hexarelin the same as GHRP-6?

No. Hexarelin is a modified analog of GHRP-6, carrying a D-2-methyl-tryptophan substitution that changes its receptor-binding characteristics. Researchers sometimes study the two side by side to compare secretagogue potency and duration of effect.

What is the CAS number for Hexarelin?

140703-51-1.

Is Hexarelin FDA approved?

No. It has never completed FDA review for any indication and is not sold as a prescription drug, OTC product, or supplement.

Is Hexarelin banned in sports?

Yes. It is explicitly listed as Examorelin under WADA’s S2.2.4 category for growth hormone-releasing peptides, alongside GHRP-2 and GHRP-6.

Has Hexarelin been tested in human trials?

Yes — unlike many research peptides, Hexarelin has a genuine body of 1990s-era published human pharmacokinetic and dose-response studies. It was not, however, advanced to regulatory approval or commercial therapeutic development.

Why is Hexarelin sold as research-use-only if it’s been studied in humans?

Historical human pharmacology studies do not equal an approved drug. Hexarelin has no FDA-approved indication, no manufacturer marketing it for clinical use, and is regulated as a research chemical accordingly.

What does a Certificate of Analysis show for a peptide like Hexarelin?

A COA documents a specific batch’s identity and purity — typically HPLC purity analysis and mass spectrometry molecular-weight confirmation — tied to that lot’s number and test date.

How should Hexarelin be stored?

At −20°C, sealed, protected from light and moisture, with reconstituted material aliquoted and stored per the specific batch’s technical data sheet.

How is Hexarelin different from Ipamorelin in research contexts?

Both are GH secretagogues studied via the GHS-R1a pathway, but they differ in receptor selectivity and reported prolactin/cortisol co-release — Ipamorelin’s literature emphasizes more selective GH-axis activity, while Hexarelin’s includes the additional CD36-mediated cardiac signaling research described above.

Does NexaPeptideLabs provide dosing or administration guidance?

No. NexaPeptideLabs does not provide dosing, administration, reconstitution-for-use, or protocol guidance of any kind, because this material is not sold or intended for human or animal use. Researchers should refer to their own institution’s protocols and published literature for experimental design.

Sources

• Ghigo et al., “Growth hormone-releasing activity of hexarelin in humans. A dose-response study”
• Maheshwari et al., “Selective lack of growth hormone response to hexarelin in GHRH-receptor deficiency”
• Cittadini et al., “The growth hormone secretagogue hexarelin improves cardiac function in rats after experimental myocardial infarction”
• Mao et al., “The Growth Hormone Secretagogue Hexarelin Protects Rat Cardiomyocytes From in vivo Ischemia/Reperfusion Injury Through Interleukin-1 Signaling Pathway”
• Arvat et al., “Arginine and growth hormone-releasing hormone restore the blunted growth hormone-releasing activity of hexarelin in elderly subjects”
• WADA Prohibited List, S2.2.4 — Growth Hormone Releasing Peptides
• U.S. FDA, Certain Bulk Drug Substances for Use in Compounding That May Present Significant Safety Risks