# Hexarelin: Evidence, Mechanism, Dosing & Legal Status

> A clinical monograph on hexarelin (examorelin) — one of the most potent growth-hormone-releasing peptides. Real human GH-provocation and acute cardiac data (Grade B), preclinical cardioprotection claims (Grade C), and a 2026 status that is unapproved and banned in sport.

*Published 2026-06-30 · Updated 2026-07-01 · By Marcus Feld, PharmD, BCPS*

The short answer
Hexarelin (examorelin) is one of the most potent growth-hormone-releasing peptides ever studied, and unusually for a research peptide it has **genuine small-scale human data** — for GH provocation and for acute, GH-independent cardiac performance — earning it evidence grade **B**. Its cardioprotection and fat-loss marketing, by contrast, rest on animal work and grade **C**. It is not FDA-approved, not legitimately compoundable, and prohibited in sport at all times under WADA.[1](https://peptidevox.com/#r1)[6](https://peptidevox.com/#r6)[16](https://peptidevox.com/#r16)

Hexarelin (examorelin; sequence His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH₂) is a synthetic hexapeptide growth-hormone secretagogue marketed in fitness and longevity circles for GH release, fat loss and "cardioprotection."[1](https://peptidevox.com/#r1) What separates it from most research peptides is that some of those claims actually have human data behind them — and others clearly do not. This monograph separates the two.

*This article is informational and editorial content for research and educational purposes only. It is not medical advice, not a protocol to follow, and not a sourcing guide. Hexarelin is not an FDA-approved drug; it is sold as a "research chemical not for human use" and is prohibited in sport. Dosing figures are reported strictly as seen in the published literature for completeness — not as recommendations. Consult a licensed clinician before any health decision.*

## What is hexarelin and how does it work?

Hexarelin is a synthetic hexapeptide; the D-2-methyl-tryptophan substitution confers metabolic stability and resistance to enzymatic degradation, making it more chemically stable and functionally more potent than endogenous ghrelin at their shared receptor.[1](https://peptidevox.com/#r1)[8](https://peptidevox.com/#r8) Unusually, it acts at two distinct receptors, which is the key to understanding both its proven and its unproven effects.

The first target is **GHS-R1a, the ghrelin receptor** — the Gq/phospholipase-C-coupled GPCR that mediates pituitary GH release. Because GHRH signals through a separate cAMP-dependent receptor, low-dose hexarelin combined with GHRH is synergistic, producing far greater GH release than either alone, and hexarelin also acts at the hypothalamic level by promoting GHRH tone and antagonizing somatostatin.[1](https://peptidevox.com/#r1) The second target is **CD36, a scavenger receptor** expressed on cardiomyocytes, microvascular endothelium, monocytes and adipocytes; photoaffinity mapping localized the binding domain to CD36 residues Asn132-Glu177, overlapping the oxidized-LDL binding site, and CD36 signaling (Src kinases, FAK, PI3K/AKT, PPAR) is the proposed basis for hexarelin's *GH-independent* cardiovascular and metabolic actions.[7](https://peptidevox.com/#r7)[8](https://peptidevox.com/#r8) Ghrelin itself binds CD36 only weakly — a key distinction.

In the human dose-response study, plasma GH rose dose-dependently, peaked at about 30 minutes and returned to baseline within roughly 240 minutes, with a GH-response half-life near 55 minutes; animal plasma half-life is about 76 minutes in rats and 120 minutes in dogs.[1](https://peptidevox.com/#r1)[15](https://peptidevox.com/#r15) The full receptor and clinical-trial context can be cross-checked against the public literature index at [PubMed](https://pubmed.ncbi.nlm.nih.gov/12144941/).

## What is the evidence by indication?

Hexarelin's evidence is genuinely tiered: two human uses reach Grade B, while the claims that dominate marketing remain animal-grade. The table below grades each indication honestly.

  Hexarelin evidence by indication

    IndicationBest evidenceGrade

    GH provocation / GH-deficiency diagnosisDouble-blind placebo-controlled dose-response in 12 men; combined hexarelin+GHRH testingB (human)
    Acute cardiac performance (GH-independent)Intra-operative study, 24 CAD bypass patients: LVEF, cardiac index & output all rose (P<0.001)B (human, early-phase)
    Cardioprotection / anti-ischemic & anti-remodelingRat ischemia-reperfusion & post-MI fibrosis models, traced to cardiac CD36C (preclinical)
    Body composition / lipid & glucose metabolismInsulin-resistant MKR mice via CD36; no human efficacy endpointsC (preclinical)
    Pediatric GH/IGF-1 therapyOpen-label intranasal series, 8 children; IGF-1 rose significantlyB-to-C (small human)

The best human data are for **GH provocation**. In the foundational double-blind, placebo-controlled, rising-dose study, 12 healthy men received IV boluses of 0.5, 1 and 2 µg/kg versus placebo; mean peak GH was 3.9, 26.9, 52.3 and 55.0 ng/mL respectively, with the 2 µg/kg dose approaching the maximal response.[1](https://peptidevox.com/#r1) Combined hexarelin plus GHRH has been proposed as an alternative to the insulin tolerance test for diagnosing GH deficiency, with high sensitivity and specificity in cited series — though hexarelin itself was never approved as a diagnostic agent (macimorelin later filled that niche).[12](https://peptidevox.com/#r12)[13](https://peptidevox.com/#r13)

The second Grade-B use is **acute cardiac performance**. In 24 male CAD patients undergoing bypass surgery, IV hexarelin produced prompt increases in left-ventricular ejection fraction, cardiac index and cardiac output (all PProven vs hyped
Proven in humans (Grade B): potent dose-dependent GH release, GHRH synergy, and acute GH-independent improvement in cardiac performance. Hyped (Grade C): durable fat loss, body recomposition and chronic human "cardioprotection" — these rest on animal and in-vitro data and were never confirmed in outcome RCTs. Clinical development was discontinued.[6](https://peptidevox.com/#r6)[9](https://peptidevox.com/#r9)

The cardioprotection and body-composition stories are where evidence thins. Hexarelin pretreatment protected GH-deficient rat hearts against ischemia-reperfusion injury via cardiac CD36, preserved myocardial function and reduced fibrosis after MI, and improved dyslipidemia and glucose tolerance in insulin-resistant mice — consistent, mechanistically coherent, but animal-grade.[7](https://peptidevox.com/#r7)[10](https://peptidevox.com/#r10)[9](https://peptidevox.com/#r9) In humans, GHS administration reliably raises GH and IGF-1 short-term, but few studies measure clinically meaningful endpoints such as body composition or function.[14](https://peptidevox.com/#r14) The fat-loss framing is not supported by human efficacy trials.

## What doses appear in the literature?

Reported strictly as information, not a protocol. For acute GH provocation and diagnostics, single IV boluses of 0.5, 1 or 2 µg/kg were used, with the 2 µg/kg dose approaching the maximal GH response; combined GH-axis testing used roughly 1 µg/kg IV with GHRH.[1](https://peptidevox.com/#r1)[12](https://peptidevox.com/#r12) The chronic-dosing human study used 1.5 µg/kg subcutaneously twice daily for 16 weeks in healthy elderly subjects — the regimen that characterized desensitization and HPA safety.[2](https://peptidevox.com/#r2)[3](https://peptidevox.com/#r3) A small pediatric IGF-1 study used 60 µg/kg intranasally three times daily in a research setting.[12](https://peptidevox.com/#r12) Hexarelin is active by IV (most pharmacology and diagnostic work), subcutaneous, intranasal and oral routes, with oral and intranasal bioavailability lower than parenteral.[1](https://peptidevox.com/#r1) Because continuous daily exposure attenuates the response, intermittent or cycled exposure is discussed in the literature as a way to preserve responsiveness.[5](https://peptidevox.com/#r5) No approved human formulation, label or pharmacy-grade product exists.

## How safe is hexarelin?

The best-characterized acute effect is endocrine spillover: hexarelin causes slight, transient increases in prolactin, cortisol and ACTH, while LH, FSH, TSH, glucose and IGF-1 are unaffected by acute dosing.[1](https://peptidevox.com/#r1) The defining chronic concern is tachyphylaxis — over 16 weeks of 1.5 µg/kg SC twice daily, the AUC-GH fell from 19.1 to 10.5 µg/L·h, but the effect was partial and reversible, returning to baseline (19.4) four weeks after stopping.[2](https://peptidevox.com/#r2) Reassuringly, that same chronic study found no sustained over-stimulation of the pituitary-adrenal axis or prolactin: basal cortisol and 24-hour urinary free cortisol were unchanged.[3](https://peptidevox.com/#r3) Higher body-fat mass markedly blunts the GH response — a pharmacodynamic limitation rather than a toxicity.[4](https://peptidevox.com/#r4)

Theoretical risks include growth-promotion of occult or active malignancy via the GH/IGF-1 axis (a class caution, not a documented hexarelin signal) and unpredictable CD36-mediated cardiometabolic effects — CD36 is central to foam-cell formation, and hexarelin competes with oxidized LDL at CD36, which preclinically reduced atherosclerotic lesions but could cut either way in humans.[8](https://peptidevox.com/#r8) Pregnancy, lactation and pediatric use outside research are precautionary contraindications. In practice, because no approved formulation exists, research-chemical hexarelin carries real purity, sterility and concentration hazards.[18](https://peptidevox.com/#r18)

## What is the FDA and WADA status in 2026?

Hexarelin is not FDA-approved for any therapeutic or diagnostic indication.[18](https://peptidevox.com/#r18) As a class, GH-secretagogue peptides were swept into Category 2 of the FDA's interim 503A bulks list — substances raising significant safety concerns, ineligible for compounding — in the September 2023 action; related GHRPs such as ipamorelin were reviewed at the October 2024 PCAC meeting with the FDA recommending against inclusion, and a further PCAC meeting on additional peptides was scheduled for July 23-24, 2026.[19](https://peptidevox.com/#r19)[20](https://peptidevox.com/#r20) Hexarelin is not on any Category-1 permitted bulks list for 503A or 503B and is not legitimately compoundable as of 2026; it is sold only as a non-human research chemical, and clinical development (GHD diagnosis, cardiac indications) was discontinued.[18](https://peptidevox.com/#r18)

For athletes the picture is unambiguous. Hexarelin is prohibited at all times, explicitly named as "examorelin (hexarelin)" among GH-releasing peptides under section S2.2.4 of the 2026 WADA Prohibited List, which took effect January 1, 2026.[16](https://peptidevox.com/#r16)[17](https://peptidevox.com/#r17) Modern LC-MS/MS methods can detect hexarelin and its metabolites, though the detection window is short. It is not a DEA-controlled substance.

**Bottom line.** Hexarelin is real, mechanistically fascinating science: a uniquely potent dual GHS-R1a/CD36 ligand with credible *acute* human cardiac data not reproduced by GHRH or recombinant GH, and well-characterized GH pharmacology — Grade B for its two genuine human uses, Grade C for the cardioprotection and body-composition claims that dominate marketing. From a functional, root-cause standpoint, the honest framing is that hexarelin is a potent investigational probe of the GH/ghrelin-CD36 axis with intriguing but unfinished human evidence — not a validated therapy. Regulatory facts here are current as of June 2026; the July 23-24, 2026 PCAC outcome was pending at the time of writing and should be re-verified after that date.

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Source: https://peptidevox.com/peptide-encyclopedia/hexarelin
Index: https://peptidevox.com/llms.txt · Full text: https://peptidevox.com/llms-full.txt