Is hexarelin more potent than other secretagogues?

It is among the more potent tested in humans, and dose-dependent growth hormone release was established in healthy volunteers in 1994. Potency is not the same as usefulness, though: it releases growth hormone strongly and non-selectively.

Does hexarelin stop working with repeated use?

One study in older adults reported that short-term administration did not desensitise the growth hormone response. That is a real finding, and it is limited to the short period studied — nothing published addresses longer use.

Why is hexarelin studied in heart research?

It binds CD36 in cardiac tissue, which is a different receptor from the one that drives growth hormone release. The cardiac findings are therefore not downstream of growth hormone, and that literature is mostly preclinical.

How does hexarelin compare with ipamorelin?

Both act at the ghrelin receptor. Hexarelin also raises prolactin, ACTH and cortisol in humans; ipamorelin's original characterisation reported growth hormone release without those rises. That difference is the reason ipamorelin exists.

Is hexarelin approved as a medicine?

No. It is supplied here as a laboratory reagent for research use only, not for human or veterinary use.

Research guides

Hexarelin (examorelin): what the research says

One of the most potent secretagogues tested in humans, with a second cardiac literature running through CD36 rather than the growth hormone axis.

Available in the catalogue

Supplied as research material. Sizes and pricing are on the product page. Availability is not a statement about what a compound does.

HEXARELIN
Growth Hormone

Hexarelin has more human endocrine data behind it than most compounds in this catalogue, and the studies are unusually direct: healthy volunteers, hormone measured, dose-response established. What that work also found is the part usually left out.

What the molecule is

A synthetic hexapeptide analogue of GHRP-6, modified for greater potency and metabolic stability. It is also published under the names examorelin and EP-23905.

The endocrine work

A double-blind placebo-controlled rising-dose study in healthy male volunteers reported dose-dependent growth hormone release, which is the finding the compound is usually described by. A separate study addressed the question that matters more for any repeated use of a secretagogue — whether the pituitary stops responding — and reported that short-term administration did not desensitise the growth hormone response in older adults.

That second result is genuinely informative and also narrow. It concerns short-term administration, and it does not establish what happens over longer periods, which is the question anyone reading about a secretagogue actually has.

The cardiac literature is about a different receptor

Hexarelin binds CD36 in cardiac tissue, a receptor unrelated to the one driving growth hormone release. That is why a whole separate strand of publication examines it in cardiovascular rather than endocrine research, and why cardiac findings cannot be read as consequences of growth hormone release. This work is predominantly preclinical.

What studies reported

Each entry states what a study examined and the model it used. Nothing below describes an outcome for a person.

Everything below is drawn from published research, and each entry names the model the study used. Approval status varies by compound and by country, and nothing described here is supplied as a medicine or for use in a person.

Imbimbo et al. (1994)European Journal of Clinical Pharmacology · 46(5):421–5
Reported dose-dependent growth hormone release in healthy male volunteers across a range of hexarelin exposures.
human, double-blind placebo-controlled rising-dose Source
Ghigo et al. (1996)European Journal of Endocrinology · 135(4):407–12
Examined whether short-term administration blunts the pituitary response, and reported that growth hormone responsiveness was not desensitised over the period studied.
human, older adults Source
Mao et al. (2014)Journal of Geriatric Cardiology · 11(3):253–8
A review of the compound's reported cardiovascular activity, including the proposal that its cardiac effects run through CD36 rather than the growth hormone axis.
review of preclinical and clinical work Source
Huang et al. (2017)International Heart Journal · 58(2):257–63
Reported protection of cardiomyocytes from ischaemia/reperfusion injury, with interleukin-1 signalling proposed as the pathway involved.
rat, ischaemia/reperfusion injury Source

Adverse and null findings reported

Harms, tolerability observations, and trials that did not meet their endpoint. A negative result is a finding and is listed here rather than omitted.

Arvat et al. (1997)Peptides · 18(6):885–91
Reported that hexarelin raised prolactin, ACTH and cortisol as well as growth hormone in man, compared against GHRH and other releasing hormones — the non-selectivity that distinguishes this compound from ipamorelin.
human, comparative endocrine study Source

What the research does not establish

An absence cannot be cited, so these are stated plainly. They are the part of the picture that silence would otherwise hide.

No published randomised controlled trial has tested hexarelin for a therapeutic outcome. The human literature measures hormone release, not clinical endpoints, and the compound holds no marketing authorisation in any jurisdiction.
The desensitisation question is answered only for short-term administration. Whether the pituitary response is maintained over months has not been published for this compound.
The cardiac literature is overwhelmingly preclinical. CD36 binding in cardiac tissue is well described in animals and cells; what it produces in humans is not established.
The rises in ACTH, cortisol and prolactin are documented in single-occasion studies. What repeated stimulation of those axes does has not been characterised.
No long-term safety data of any kind has been published for this compound in humans.

Common questions

Is hexarelin more potent than other secretagogues?: It is among the more potent tested in humans, and dose-dependent growth hormone release was established in healthy volunteers in 1994. Potency is not the same as usefulness, though: it releases growth hormone strongly and non-selectively.
Does hexarelin stop working with repeated use?: One study in older adults reported that short-term administration did not desensitise the growth hormone response. That is a real finding, and it is limited to the short period studied — nothing published addresses longer use.
Why is hexarelin studied in heart research?: It binds CD36 in cardiac tissue, which is a different receptor from the one that drives growth hormone release. The cardiac findings are therefore not downstream of growth hormone, and that literature is mostly preclinical.
How does hexarelin compare with ipamorelin?: Both act at the ghrelin receptor. Hexarelin also raises prolactin, ACTH and cortisol in humans; ipamorelin's original characterisation reported growth hormone release without those rises. That difference is the reason ipamorelin exists.
Is hexarelin approved as a medicine?: No. It is supplied here as a laboratory reagent for research use only, not for human or veterinary use.

Compounds covered

The reference page for each compound this article discusses.

Hexarelin

GHRP-6: what the research says
The first growth hormone releasing peptide, and the one whose lack of selectivity is why every later secretagogue exists. It also raises cortisol and appetite.
Ipamorelin: what the research says
A selective growth hormone secretagogue with a completed, published human trial. It missed its primary endpoint, and that is the most useful result it has.
Peptide shelf life and stability
How long lyophilised and reconstituted peptides keep, and the four things that shorten it: temperature, moisture, light and oxidation. Storage figures included.

About this article

Everything reported here comes from published research, and each finding names the model the study used — cell culture, rat, or human. Findings in one model do not transfer to another, most of the work described is preclinical, and none of it is a claim that a compound is safe or effective for any purpose. Nothing on this page describes doses, routes of administration, or use in a person.

Approval status varies by compound and by country. A few of the substances described are the active ingredient of medicines authorised in the EU; most have no marketing authorisation anywhere and have never been assessed by a regulator. Neither is supplied as a medicine here. All material supplied by ASSAY is sold for in-vitro laboratory research only, and is not a drug, food, cosmetic or medical device, and not for human or veterinary use.

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