Hexarelin: evidence, FDA status and research

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 lab-made peptide with six amino acids. It comes from GHRP-6, with a methyl group added to one tryptophan. This change made it more stable and more potent. Europeptides developed it in the 1990s. Ghigo's group in Turin studied it widely as a test for growth hormone deficiency and a possible treatment. ³²

Like the other GHRPs, it acts through the ghrelin receptor and not the GHRH receptor. It also binds a second receptor, CD36. This is the basis of the heart research that keeps it in use online. ¹³

How it works

At the pituitary and hypothalamus, hexarelin activates GHS-R1a. This releases a pulse of growth hormone. In healthy young adults the pulse is bigger than the response to the same dose of GHRH. Reviews from that time note that the effect appears after doses by vein, under the skin, in the nose and by mouth. It partially desensitises with repeated use. ³

In the heart, hexarelin binds CD36. This is 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. This effect was absent in hearts from mice and rats lacking CD36. Later animal studies built on this and reported protection against ischaemic injury. No one has tested this in people. ¹

What human research shows

Arvat and colleagues gave single doses of hexarelin and GHRP-2 by vein to six healthy young adults and six elderly subjects. They compared both with GHRH. In the young adults, both peptides gave a growth hormone response larger than GHRH. In the elderly subjects it was smaller than in the young. The two peptides were indistinguishable from each other. Both raised prolactin, ACTH and cortisol. The cortisol rise was similar to that from corticotropin-releasing hormone. ²

Reviews of the GHRP class record that long use 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

Short studies report no serious side effects. But hexarelin is not selective. It raises cortisol and prolactin along with growth hormone. The authors of the comparison study called out this lack of specificity directly. No one has studied long-term use in humans. So the effects on glucose tolerance, blood pressure and tumour growth are unknown. 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 studied in the 1990s but was never approved in the US or elsewhere. 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. This is based on direct comparisons in healthy adults. Potency at releasing a hormone pulse is not the same as an effect on muscle. No study has measured that. ²

Does hexarelin protect the heart?

That idea comes from rodent and cell studies. They show hexarelin binds a heart receptor, CD36, and alters coronary blood flow. There are no human heart trials. ¹

What unwanted effects appeared in human studies?

In the short 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