Overview
The most potent GH releaser of the classical GHRP family, and the one that desensitises fastest. Its more interesting biology may be cardiac rather than pituitary — it binds CD36 in heart tissue independently of GH.
Not approved for human use anywhereNo approval anywhere for human use. Sold under research-use labelling. Not approved for human use.
| Regulatory status | Not approved. Studied in cardiac research; abandoned for therapeutic development. |
|---|---|
| Drug class | Synthetic hexapeptide GH secretagogue |
| Route | Subcutaneous or intravenous (research) |
| Half-life | ~55 minutes |
| Evidence rating |
2/5 Limited
Evidence rating 2 out of 5: Limited
Preclinical work plus scattered human reports, uncontrolled use, or negative trials. |
| Studied in | Acute GH-release pharmacology in humans; preclinical cardiac ischemia models; small human cardiac studies. |
How it works
Ghrelin receptor agonism producing a large GH pulse, plus binding to the CD36 scavenger receptor in cardiac and vascular tissue, which mediates GH-independent cardioprotective effects in animal models.
Evidence base
Rated 2 of 5 — Limited. Preclinical work plus scattered human reports, uncontrolled use, or negative trials.
- Acute human pharmacology well described; no chronic efficacy or safety data.
Benefits & potential uses
Bars indicate how well each claim is supported: three = strong human evidence, two = moderate, one = preliminary or preclinical.
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Highest GH release potency in class Moderate evidence
Produces larger acute GH pulses than GHRP-2 or GHRP-6.
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GH-independent cardioprotection signals Preliminary
Preclinical models show improved cardiac function after ischemia via CD36, independent of GH.
-
Retains some activity in GH-deficient states Preliminary
The cardiac effects do not require an intact GH axis.
Risks, cons & cautions
Bars indicate seriousness: three = serious or common, two = moderate, one = minor.
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Rapid and marked tachyphylaxis Moderate evidence
GH response falls substantially within about two weeks of continuous use — arguably the defining practical problem.
-
Cortisol and prolactin elevation Moderate evidence
Significant; more than GHRP-2.
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No approved indication Serious
Development was not completed for any use.
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Cardiac effects unstudied in chronic human use Serious
The CD36 biology is interesting but entirely uncharacterised long-term in people.
-
Unregulated supply Serious
Research-chemical market.
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WADA prohibited Minor
Banned in sport.
Who should avoid it
- Active malignancy
- Pregnancy
- Cardiac disease outside a research setting
- Hyperprolactinemia
If used under medical supervision, monitor
- IGF-1, prolactin, cortisol
- Glucose
Regulatory & legal status
Not approved for human use.
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Where to read further
We link to live literature searches rather than a frozen citation list, so you always see current results — including anything published after our last review.
- PubMed — all published literature on Hexarelin
- PubMed — randomized controlled trials only
- ClinicalTrials.gov — registered human trials
Related peptides in Growth Hormone Axis
Terms used on this page
- Growth Hormone-Releasing Peptide (GHRP)
- GHRPs are small synthetic peptides that release growth hormone by activating the ghrelin receptor GHS-R1a on pituitary and hypothalamic cells rather than the GHRH receptor.
- Growth Hormone Secretagogue Receptor (GHS-R1a)
- GHS-R1a is the G protein-coupled ghrelin receptor mediating growth hormone release and appetite, notable for unusually high constitutive activity in the complete absence of any ligand.
- Preclinical Study and Animal Model
- Preclinical studies are the laboratory, cell and animal experiments done before any human exposure, establishing mechanism, target engagement and the toxicology package that permits a first trial.
- Pulsatile GH Secretion
- Pulsatile GH secretion is the discontinuous release of growth hormone in discrete bursts separated by near-undetectable troughs, generated by alternating GHRH and somatostatin drive.
- Agonist
- An agonist is a ligand that binds a receptor and stabilises its active conformation, producing a biological response rather than merely occupying the binding site.
- Tissue Perfusion
- Tissue perfusion is the volume of blood delivered through the capillary bed per unit of tissue mass per minute, the quantity that determines local oxygen and drug delivery.
This page is educational information, not medical advice. It cannot account for your medical history, medications, or risk factors. Do not start, stop or change any treatment based on it. Speak to a qualified healthcare professional who knows your case.