All peptides / Muscle and bone
Hexarelin
GHRP / ghrelin agonist
Also Examorelin, Hexarelin acetate, EP 23905, EP-23905, Hexarelin peptide
- Evidence
- CAnimal and cell studies
- FDA status
- Not approvedas of 2026-10-26
- Route
- Injection
- Studies cited
- 1 human1 animal or cell
Sold to build muscle and protect the heart. It makes the body release growth hormone, but also stress hormone, and the heart claims come only from animal studies.
Sold for
Hexarelin is sold as the most potent of the growth hormone-releasing peptides, for muscle gain and for heart protection.
Studies say
Hexarelin produces a larger growth hormone pulse than GHRH in healthy adults but also raises cortisol and prolactin, and its cardiac effects have been shown only in animals, so the grade is C.
Why grade C. For the muscle-building use hexarelin is sold for, the cited human evidence is an acute hormone study in six young and six elderly adults showing a growth hormone pulse along with rises in prolactin, ACTH and cortisol. The heart claims come from rodent and cell work on the CD36 receptor. No trial has measured body composition or any clinical outcome. 21
FDA. Hexarelin, also called examorelin, is not approved by the FDA for any use and is sold online as a research chemical. It was studied in the 1990s as a growth hormone test and therapy but never reached the market anywhere. 3
Written from 3 cited sources. Fact-checked 2026-10-27: 11 claims checked, 2 corrected. Last refreshed 2026-10-27. Not physician reviewed.
What this means for you
- What people take it for
- Muscle gain and heart protection.
- Can a US doctor prescribe it?
- No. It is not approved and is sold as a research chemical.
- Properly tested in people?
- Not properly: animal or lab studies, or small uncontrolled human reports. small short tests in healthy people, with no muscle or heart results.
Evidence checklist
- Randomised controlled trial Acute hormone study, no randomizationno
- Human study over 100 people Cited human study had 12 peopleno
- More than one research group Mostly one Turin research groupno
- Clinical outcomes, not surrogate markers Hormone levels only; no body or heart outcomesno
- Human safety data beyond case reports Acute studies only; long-term unknownno
Drawn from the cited studies below. A dash means the sources give no information.
What it is
Hexarelin is a synthetic six-amino-acid peptide derived from GHRP-6 by adding a methyl group to one tryptophan, a change that made it more stable and more potent. It was developed in the 1990s by Europeptides and studied extensively by Ghigo's group in Turin as a diagnostic and possible treatment for growth hormone deficiency. 32
Like the other GHRPs it acts through the ghrelin receptor and not the GHRH receptor, and it binds a second receptor, CD36, which is the basis of the heart research that keeps it in circulation online. 13
How it works
At the pituitary and hypothalamus, hexarelin activates GHS-R1a and releases a pulse of growth hormone that in healthy young adults exceeds the response to the same dose of GHRH. Reviews from the period note the effect appears after intravenous, subcutaneous, intranasal and oral administration and partially desensitises with repeated exposure. 3
In the heart, hexarelin binds CD36, a scavenger receptor found on heart muscle cells and the lining of small blood vessels. Bodart and colleagues showed in 2002 that hexarelin raised coronary perfusion pressure in isolated rodent hearts and that this effect was absent in hearts from mice and rats lacking CD36. Later animal studies built on this to report protection against ischaemic injury, none of which has been tested in people. 1
What human research shows
Arvat and colleagues gave six healthy young adults and six elderly subjects single intravenous doses of hexarelin and GHRP-2 and compared them with GHRH. Both peptides produced a growth hormone response larger than GHRH in the young adults and smaller in the elderly subjects than in the young, the two were indistinguishable from each other, and both raised prolactin, ACTH and cortisol, with the cortisol rise similar to that produced by corticotropin-releasing hormone. 2
Reviews of the GHRP class record that prolonged administration raises IGF-1 in humans, but no hexarelin trial in the citation set measured muscle mass, strength, fat or heart function. 3
| Study | Model | Finding |
|---|---|---|
| Arvat 1997, GHRP-2 and hexarelin in man | Humans, n=6 young and n=6 elderly adults, single intravenous doses | Hexarelin and GHRP-2 gave equal growth hormone responses, larger than GHRH in the young, and both raised prolactin, ACTH and cortisol. 2 |
| Bodart 2002, CD36 | Rat cardiac membranes and isolated perfused rat and mouse hearts | Hexarelin bound CD36 in heart tissue, and its coronary vasoconstrictor effect was absent in hearts lacking CD36. 1 |
| Ghigo 1997, GHRP review | Narrative review of human and animal studies | Hexarelin and other GHRPs release growth hormone by several routes, desensitise with continuous use and raise IGF-1 over time. 3 |
Safety
Acute studies report no serious adverse events, but hexarelin is not selective: it raises cortisol and prolactin alongside growth hormone, and the authors of the comparative study called this lack of specificity out directly. Long-term use has not been studied in humans, so effects on glucose tolerance, blood pressure and tumour growth are unknown, and research-chemical products are not tested for purity or sterility. 23
Questions for your clinician
- Is there any controlled human trial showing hexarelin builds muscle?
- How might raised cortisol and prolactin affect me?
- What is known about long-term growth hormone stimulation?
Questions people ask
Is hexarelin FDA-approved?
No. Hexarelin was investigated in the 1990s but was never approved in the US or elsewhere, and online products are sold as research chemicals. 3
Is hexarelin stronger than GHRP-6 or GHRP-2?
It is more potent than GHRP-6 and about equal to GHRP-2 at releasing growth hormone, based on direct comparisons in healthy adults. Potency at releasing a hormone pulse is not the same as an effect on muscle, which no study has measured. 2
Does hexarelin protect the heart?
That idea comes from rodent and cell studies showing hexarelin binds a cardiac receptor, CD36, and alters coronary blood flow. There are no human cardiac trials. 1
What unwanted effects appeared in human studies?
In the acute human study hexarelin raised cortisol, ACTH and prolactin as well as growth hormone, so it is not a clean growth hormone releaser. Longer-term effects in people are not documented. 2
Citations
- Bodart 2002, Circulation Research: CD36 mediates the cardiovascular action of growth hormone-releasing peptides in the heart doi.org
- Arvat 1997, Peptides: effects of GHRP-2 and hexarelin on GH, prolactin, ACTH and cortisol in man pubmed.ncbi.nlm.nih.gov
- Ghigo 1997, European Journal of Endocrinology: growth hormone-releasing peptides, review pubmed.ncbi.nlm.nih.gov