Hexarelin: the basics
What is it?
A lab-made chain of six amino acids, closely related to GHRP-6, that makes the pituitary gland release a large burst of growth hormone.
Research paper 1 ↗Research paper 2 ↗Research paper 3 ↗What do people claim it helps with?
Sellers promote it for muscle growth, fat loss, recovery and heart health. These uses have not been proven in reliable treatment trials.
What has research actually shown?
In people it causes a strong, short rise in growth hormone and also raises stress hormones like cortisol. With repeated use for months, the growth hormone response got weaker.
Research paper 1 ↗Research paper 2 ↗Research paper 3 ↗Has this been demonstrated in people?
Short human hormone studies from the 1990s and 2000s, small single-dose heart studies, and animal research. There are no large or long-term treatment trials.
Research paper 1 ↗Research paper 2 ↗Research paper 3 ↗What side effects, risks and unknowns should I understand?
It raises cortisol, ACTH and prolactin as well as growth hormone. Long-term safety in people is unknown because it was only studied briefly in small groups.
Research paper 1 ↗Research paper 2 ↗Is it an approved medicine?
No FDA-approved medicine contains this peptide. Availability online or through a clinic does not mean it has been approved.
Research paper ↗Approval here means U.S. FDA approval and applies to a particular product, formulation and use. This is a starting overview, not a complete side-effect list. Sources checked 10 October 2026; independent scientific review pending.
How is it used or studied?
Studied mainly as an injection in research settings. There is no FDA-approved formulation; products sold online are not the material used in studies.
Different routes and formulations can have different effects. A study of one product does not validate every product with the same peptide name.
A common misunderstanding
A short rise in heart pumping after one dose in a lab study is not the same as a treatment that helps people with heart disease live longer or feel better.
What should I ask a clinician?
- What diagnosis or goal are we trying to address, and what established options are available?
- Was the expected benefit shown in people like me, using this exact product?
- How could my medicines, health conditions or pregnancy plans affect the risks?
- What monitoring is needed, and what would tell us the treatment is helping or should be stopped?
What do the research words mean?
- Peptide
- A short chain of amino acids, the building blocks of proteins.
- Preclinical
- Research in cells, tissues or animals before dependable treatment evidence in people.
- Controlled trial
- A study comparing a treatment with another treatment or a placebo to help separate its effects from other explanations.
- Biomarker
- A measurement, such as a hormone level. A change does not necessarily mean someone feels better or lives longer.
Hexarelin Evidence & Clinical Profile
Human Study Limits
Hexarelin has been investigated in clinical contexts. Patient outcomes must be evaluated against study size, design, and control cohorts.
Laboratory & In Vivo Assays
Cellular and animal disease models examine receptor binding affinities and signaling cascades, which require human confirmation.
What is Hexarelin?
Hexarelin (Examorelin) is Hexarelin, also called examorelin, is a synthetic six-amino-acid relative of GHRP-6 that strongly triggers growth hormone release and also raises ACTH, cortisol and prolactin. Most human data come from short 1990s hormone tests and small heart-function studies. It has never been approved as a medicine in the U.S. Aliases include: Examorelin, EP-23905, MF-6003, His-D-2-Me-Trp-Ala-Trp-D-Phe-Lys-NH2.
- Sequence (one-letter)
- H-(D-2-Me-W)-A-W-(D-F)-K-NH2
- Molecular formula
- C47H58N12O6
- Molecular weight
- 887.0 g/mol
- CAS Number
- 140703-51-1
- UNII Code
- 09QF37C617
- PubChem CID
- 6918297
Identifiers checked against PubChem and FDA's Global Substance Registration System on 13 October 2026. FDA substance record ↗ · PubChem record ↗ See all names and codes in the peptide name index.
Clinical Trials & Human Cohorts
Human research can examine tolerability, symptoms or patient outcomes. The design and comparator determine what each result can establish.
ACTH- and cortisol-releasing effect of hexarelin in normal subjects and patients with Cushing's syndrome [1]
What was reported
In healthy adults a single intravenous administration raised ACTH and cortisol about as much as the hormone CRH. The response was much larger in Cushing's disease.
What limits the conclusion
Single-administration hormone study. It shows hexarelin is not selective for GH, but does not measure clinical outcomes.
Cardiac effects of hexarelin in hypopituitary adults [2]
What was reported
Left ventricular ejection fraction rose briefly after a single administration, even in GH-deficient men who released little GH.
What limits the conclusion
Tiny, single-administration study; a short rise in pumping fraction is not proof of a heart treatment.
GH-independent cardiotropic activities of hexarelin in patients with severe left ventricular dysfunction [3]
What was reported
Ejection fraction rose after hexarelin in ischemic cardiomyopathy but not in dilated cardiomyopathy, despite similar GH release.
What limits the conclusion
Thirteen patients, compared with control groups studied earlier, and only acute effects measured.
How the compound may work
Mechanisms describe how Hexarelin may affect biological processes. Laboratory findings and patient outcomes answer different questions.
GHS-R1a agonism
Hexarelin is a GH-releasing peptide that acts on the GH secretagogue receptor (GHS-R1a), later identified as the ghrelin receptor. [6]
Possible direct heart effects
Ejection fraction changes in people who released little GH led researchers to propose GH-independent cardiac actions. Rat infarction studies support this idea, but it remains unproven in patients. [5]
Areas Being Studied
These research topics reflect active areas of scientific exploration, distinct from unverified commercial marketing claims.
Pituitary testing
GH, ACTH and cortisol responses as probes of pituitary function and Cushing's disease. [1]
Heart function
Short-term ejection-fraction changes; no outcome trials in heart failure. [3]
Repeated use and tolerance
The GH response partly weakened with repeated use and recovered after stopping; IGF-I, body composition and bone density did not change significantly. [4]
Compare the study designs.
| Study | Design / sample | Outcome type | Key limitation |
|---|---|---|---|
| ACTH & cortisol release · 1997 [1] | Comparative human endocrine study n = 29 |
Clinical endpoint evaluation | Single-administration hormone study. It shows hexarelin is not selective for GH, but does not measure clinical outcomes. |
| Heart function, GHD adults · 1999 [2] | Acute open study with controls n = 16 |
Clinical endpoint evaluation | Tiny, single-administration study; a short rise in pumping fraction is not proof of a heart treatment. |
| Cardiomyopathy · 2002 [3] | Acute comparative study n = 13 |
Clinical endpoint evaluation | Thirteen patients, compared with control groups studied earlier, and only acute effects measured. |
Regulatory Status & Clinical Safety
Regulatory Classification
Not FDA-approved and not listed in FDA's 503A or 503B bulk-substance categories as of October 2026. WADA S2 prohibited substance (named as examorelin/hexarelin).
Safety Realities & Impurities
Safety depends on the molecule, formulation, route and evidence. A laboratory purity measurement alone cannot establish safety for human use.
Clinical Trials Registry Records
Official registry records from ClinicalTrials.gov. Study registration does not imply government endorsement or guaranteed efficacy.
WADA & Anti-Doping Regulations
WADA Section S2: Prohibited Substance
The World Anti-Doping Agency (WADA) classifies Hexarelin under Section S2 of the Prohibited List. Prohibited at all times (in- and out-of-competition). Last verified: October 2026.
Research Timeline
-
1996
Receptor identified
The GH secretagogue receptor that hexarelin activates is cloned. [6]
-
1997
Not GH-selective
Human studies show hexarelin raises ACTH and cortisol as well as GH. [1]
-
1998
Tolerance reported
A 16-week study finds a partial, reversible loss of GH response with repeated use. [4]
-
2000
Rat heart study
Hexarelin improves heart function in rats after experimental heart attack. [5]
-
2026
Banned in sport
WADA's 2026 Prohibited List names examorelin (hexarelin) in class S2. [7]
What Researchers Still Don't Know
Long-term safety profiles
Multi-year observational data in broader heterogeneous cohorts remains uncharacterized.
Optimal dose-response thresholds
Comparative trials optimizing minimal effective exposure versus adverse event rates.
Formulation bioavailability
Differences between oral, subcutaneous, and modified peptide delivery vehicles.
References
Primary sources verified against PubMed / NLM and regulatory databases.
- Human endocrine study
-
Human cardiac study
Cardiac effects of hexarelin in hypopituitary adults. ↗ (external website)
- Human cardiac study
-
Human long-term study
Growth hormone status during long-term hexarelin therapy. ↗ (external website)
- Animal study (rats)
- Receptor cloning study
-
Anti-doping rule
World Anti-Doping Code International Standard: Prohibited List 2026 ↗ (external website)