Hexarelin.
Hexarelin (examorelin) is a synthetic hexapeptide growth hormone secretagogue (GHS), structurally derived from the GHRP-6 family of growth hormone-releasing peptides.
Hexarelin (examorelin) is a synthetic hexapeptide growth hormone secretagogue (GHS), structurally derived from the GHRP-6 family of growth hormone-releasing peptides. Hexarelin is research / preclinical, and PepCue grades its published evidence D tier (38/100). This is a research reference, not medical or dosing advice.
What it is
Hexarelin (examorelin) is a synthetic hexapeptide growth hormone secretagogue (GHS), structurally derived from the GHRP-6 family of growth hormone-releasing peptides. It is an investigational compound that was studied in the 1990s and 2000s as a potential agent for probing and stimulating growth hormone secretion and, separately, for direct effects on the heart. It is not an approved drug.
How it works
Hexarelin acts as an agonist at the growth hormone secretagogue receptor type 1a (GHS-R1a), the same pituitary/hypothalamic receptor activated by the natural hormone ghrelin. Receptor binding engages Gq/11-phospholipase C signaling, mobilizing intracellular calcium in pituitary somatotrophs and triggering pulsatile growth hormone release; this pathway is distinct from and synergistic with GHRH, and also opposes somatostatin tone. Hexarelin additionally binds CD36, a scavenger receptor expressed in cardiac and vascular tissue, which is the proposed basis for GH-independent cardiovascular effects observed in animal models. Because it is a non-selective secretagogue, it also stimulates ACTH/cortisol and prolactin release to a greater degree than more selective agents.
Mechanism pathways
Acting on the ghrelin / GH-secretagogue receptor, a pathway separate from GHRH.
The growth hormone secretagogue receptor, GHS-R1a, is a G-protein-coupled receptor expressed on pituitary somatotrophs and in hypothalamic nuclei. Its natural ligand is ghrelin, the stomach-derived hormone associated with hunger. Activation raises growth hormone through a route entirely separate from GHRH: it acts directly on somatotrophs, and it also suppresses hypothalamic somatostatin tone, effectively releasing the brake at the same time as pressing the accelerator. This dual action is why compounds at this receptor and GHRH analogs are often studied together, since combining them produces a larger growth hormone response than either produces alone. The history here is unusual. The synthetic peptides in this group were developed in the 1980s and 1990s by working backwards from observed growth hormone release, years before ghrelin itself was identified in 1999. They were the pharmacological tools that led researchers to the receptor. They are therefore best understood as synthetic ghrelin mimetics that happened to be discovered before the hormone they mimic. Members of this group differ chiefly in selectivity, which is the practical distinction that matters most. GHS-R1a activation is not confined to growth hormone. Because the receptor sits on cells that also govern prolactin and adrenocorticotropic hormone release, and because ghrelin signalling drives appetite and influences gastric motility, several of these compounds raise cortisol and prolactin and increase hunger alongside the intended growth hormone effect. Others were specifically designed to avoid that, producing a comparatively clean growth hormone response with minimal spillover onto the other axes. Some also show additional activity at the CD36 receptor, which has been studied in cardiac contexts. Honest assessment of clinical relevance: the acute receptor pharmacology is well characterised, including in short human studies where growth hormone reliably rises after administration. That is proof of mechanism. What does not exist for this class is proof of benefit. No compound in this group is an approved medicine, controlled trials of sustained use with body composition or clinical endpoints are essentially absent, and material sold under these names is unregulated research-grade product of uncertain content. Growth hormone secretagogues are also prohibited in sport by anti-doping authorities. A further consideration specific to this receptor is desensitisation: sustained agonism at a G-protein-coupled receptor commonly reduces its responsiveness over time, so the acute hormonal response observed in a short study is not a reliable guide to what happens with continued use.
The evidence
Human data exist but are limited to small, short-term, acute physiology studies rather than outcome trials. Acute intravenous hexarelin reliably raised serum growth hormone in healthy volunteers and was compared head-to-head with GH in a controlled human study (Imbimbo/Ghigo group, J Endocrinol Invest 1999, PMID 10342360). Separate small studies reported short-lasting increases in left ventricular ejection fraction and cardiac output in normal subjects, GH-deficient patients, and dilated-cardiomyopathy patients, effects that appeared GH-independent (Bisi/Broglio et al., Endocrine 2001, PMID 11322491). A chronic-administration study found that GH responses desensitized over weeks and characterized effects on the pituitary-adrenal axis and prolactin (Clin Endocrinol 1999, PMID 10341859). Most cardioprotection evidence (CD36-mediated ischemia/reperfusion protection, IL-1 signaling) is preclinical and rodent-based (e.g., Int Heart J 2017, PMID 28321024; review J Geriatr Cardiol 2014, PMID 25278975); none of this advanced to a successful human cardiac outcome trial, and clinical development was discontinued.
The evidence, in brief
A hexapeptide GH secretagogue that potently stimulates GH release in small human studies; its much-discussed cardioprotective effects are shown mainly in animal models. Human evidence is short-term and small-scale, and it is not FDA-approved.
- Growth hormone release by the novel GH-releasing peptide hexarelin in patients with β-thalassemiaJ Pediatr Endocrinol Metab, 1997 (PMID 9364340)
Evidence maturity
An evidence-only reading: approval status, human vs preclinical data, mechanism and safety. Popularity never raises it. Research file #028
Mostly preclinical or mechanistic; little human data.
Some early human evidence exists but isn't definitive.
Claim receipts
Popular claims about Hexarelin, checked against the state of the evidence. The verdict describes evidence maturity, never an invented study result.
Small acute human studies reported short-lasting cardiac changes; no successful human cardiac outcome trial followed.
GH responses desensitize measurably with repeated or continuous administration.
It raises cortisol, ACTH and prolactin alongside GH, so the signal is not clean.
No large or extended human trials were completed, and clinical development was discontinued.
Safety profile
Documented effects in human studies include hexarelin's lack of GH selectivity: it raises cortisol, ACTH, and prolactin alongside growth hormone, so it does not produce a clean GH signal. A well-described limitation is rapid tachyphylaxis/desensitization, with attenuated GH responses on repeated or continuous dosing demonstrated both in vitro (second-messenger level) and over weeks of human administration. Long-term safety in humans is essentially unknown because no large or extended trials were completed; chronic GHS-driven IGF-1 elevation raises theoretical concerns common to this class (fluid retention, insulin sensitivity changes, and the general caution that growth-promoting signaling could be undesirable in the setting of malignancy), but these are not established for hexarelin specifically. There is no established safety profile for non-clinical/self-administered use.
Compound notes
- Hexarelin is a growth-hormone-releasing peptide (GHRP) and ghrelin-receptor agonist that strongly stimulates GH release.
- Continued exposure can cause receptor desensitization; it has also been studied for direct cardiac effects.
- Not FDA-approved; research-only.
- Like other GHRPs it can affect cortisol/prolactin; long-term safety is unknown.
Regulatory status
Hexarelin is investigational and has never received FDA or EMA marketing approval; its clinical development was discontinued. It is prohibited in sport at all times by WADA as a growth hormone secretagogue / GH-releasing peptide under category S2 of the Prohibited List, and it is generally sold only as a research-use-only chemical.
Sold research-use-only; human evidence is limited or preclinical.
By the numbers
- 01Synthetic hexapeptide GHS in the GHRP-6 family; also known as examorelin
- 02Dual receptor activity: agonist at the ghrelin receptor GHS-R1a and binder of cardiac/vascular CD36
- 03Less GH-selective than ipamorelin: also stimulates cortisol, ACTH, and prolactin
- 04Prone to rapid desensitization (tachyphylaxis) with repeated or continuous dosing
- 05Human cardiovascular findings are small, acute, and short-lasting; cardioprotection evidence is mostly rodent preclinical
- 06Never approved; banned by WADA under category S2
Hexarelin: research formats
Choose the format you are researching to see route-specific notes.
Potent GHRP; requires acetic acid for reconstitution due to its aggregation at neutral pH.
Hexarelin is a potent ghrelin-receptor agonist sold as a 2 mg vial. It belongs to the GHRP class and aggregates at neutral pH, so it requires initial reconstitution in 0.6% acetic acid, then dilution with BAC water. Reconstituting 2 mg in 2.0 mL (acetic acid first, then BAC water to volume) gives 1,000 mcg/mL.
Reconstitution: add 0.2–0.3 mL of 0.6% acetic acid first and swirl gently until dissolved, then add BAC water to total 2.0 mL. Adding BAC water directly causes precipitation.
Sources
Every factual claim above resolves to a real, published source.
- Acute cardiovascular and hormonal effects of GH and hexarelin, a synthetic GH-releasing peptide, in humansJournal of Endocrinological Investigation, 1999, PMID 10342360
- Growth hormone-independent cardiotropic activities of growth hormone-releasing peptides in normal subjects, in patients with growth hormone deficiency, and in patients with idiopathic or ischemic dilated cardiomyopathyEndocrine, 2001, PMID 11322491
- The effect of chronic hexarelin administration on the pituitary-adrenal axis and prolactinClinical Endocrinology, 1999, PMID 10341859
- The cardiovascular action of hexarelin (review)Journal of Geriatric Cardiology, 2014, PMID 25278975
Cite this page
PepCue. “Hexarelin: the evidence.” PepCue, reviewed June 1, 2026. https://www.pepcue.app/p/hexarelin.
Log your doses, run the vial math, and keep a provider-ready record in PepCue.