Hexarelin

What it is

Hexarelin and examorelin are names for the same defined substance. FDA's record also links EP-23905 and MF-6003. That identity does not make Hexarelin interchangeable with every other growth-hormone secretagogue.

Hexarelin/examorelin is distinct from GHRP-2/pralmorelin and GHRP-6/Hexapeptide-2. A Hexarelin acetate name adds a form claim but does not authenticate active ingredient, formulation, route, purity, sterility, aggregation state, or stability.

Why people care

Reader interest centers on growth hormone, physique, recovery, longevity, and cardioprotection claims, while the human record is mostly acute physiology and the cardiovascular observations are short, small, and endpoint-specific.

What humans actually show

Hexarelin has small human studies showing acute endocrine and cardiac-performance effects and a narrow 16-week endocrine follow-up, but no identified controlled evidence establishing muscle, fat-loss, recovery, anti-aging, or patient-important cardiovascular benefit. FDA's 2025 Darmerica warning letter also documents an active-ingredient listing mismatch for one Hexarelin acetate record.

• randomized human — Twelve healthy adult men in a double-blind placebo-controlled rising-exposure study; Route: Single intravenous research challenges; Outcome: Acute growth-hormone response: Hexarelin produced an exposure-related acute GH response that approached a plateau at the higher tested conditions. The seam: Very small single-exposure study; Hormone endpoint rather than muscle, fat, recovery, sleep, or clinical benefit; No chronic safety characterization; Does not authenticate another product.
• randomized human — Twelve healthy volunteers in a randomized double-blind endocrine experiment; Route: Single intravenous research challenge with naloxone or placebo conditions; Outcome: GH, prolactin, ACTH, cortisol, and TSH: Hexarelin increased GH, prolactin, ACTH, and cortisol and did not change TSH in the reported experiment. The seam: Acute endocrine physiology; Small sample; Does not define chronic adverse-effect incidence; No patient-important outcome.
• other human — Elderly subjects followed during 16 weeks of repeat Hexarelin exposure; Route: Repeated subcutaneous research exposure; Outcome: ACTH, cortisol, prolactin, urinary free cortisol, and related endocrine measures: The abstract reported no persistent pituitary-adrenal or prolactin overstimulation under the studied conditions and a lower cortisol response at week 16 that was no longer different from baseline after follow-up. The seam: The abstract does not describe the participants as healthy; No placebo control described in the abstract; Narrow endocrine safety endpoints; Does not establish broad long-term safety; Does not establish physique, recovery, longevity, or clinical benefit.
• other human — Seven healthy male volunteers; Route: Single intravenous research challenge; Outcome: Growth hormone, cortisol, left-ventricular ejection fraction, blood pressure, and heart rate during a short observation window: Hexarelin increased GH, cortisol, and left-ventricular ejection fraction for a short period without reported mean blood-pressure or heart-rate changes. The seam: Seven participants; Acute surrogate endpoint; No symptoms or cardiovascular events; No chronic treatment or safety inference.
• other human — Eight patients with dilated cardiomyopathy and five with ischemic cardiomyopathy, compared with previously studied groups; Route: Single intravenous research challenge; Outcome: Growth hormone and radionuclide left-ventricular ejection fraction: Ejection fraction increased acutely in the ischemic subgroup but not the dilated-cardiomyopathy subgroup despite GH responses in both. The seam: Very small nonrandomized subgroups; Acute surrogate endpoint; Historical comparison groups; No patient-important cardiovascular outcome.
• other human — Twenty-four men in total across four comparison arms, all with coronary artery disease and undergoing bypass surgery under general anesthesia; Route: Single intravenous research challenge; Outcome: Intraoperative ejection fraction, cardiac index, cardiac output, pressures, and systemic vascular resistance: Hexarelin increased several acute cardiac-performance measures versus the study comparisons during the observation window. The seam: The abstract does not state random allocation; The 24-person total was divided across four arms; Anesthetized perioperative setting; Acute hemodynamic endpoints; No longer-term symptoms, events, or mortality outcome; Does not establish chronic treatment benefit.

Mechanistic and nonhuman evidence

• cell — Chinese hamster ovary cells expressing human growth-hormone secretagogue receptor; Route: In-vitro Hexarelin exposure; Outcome: Intracellular calcium signaling and rapid receptor desensitization: Hexarelin produced a receptor-specific calcium response followed by marked short-interval desensitization in the cell model. The seam: Engineered cell system; Does not establish a human clinical outcome; Does not create a dosing or cycling recommendation.
• animal — Rats studied with coronary microvascular imaging and a pulmonary-hypertension model; Route: Acute and chronic experimental animal administration; Outcome: Coronary microvascular responses, right-ventricular hypertrophy, and cardiomyocyte relaxation: Acute Hexarelin caused coronary microvascular dilation, while chronic exposure did not prevent right-ventricular hypertrophy or relaxation impairment in the pulmonary-hypertension model. The seam: Animal model; Mixed endpoint-specific findings; Does not establish human cardioprotection or safety.

FDA and U.S. status

An exact active-ingredient Drugs@FDA API search returned no Hexarelin or examorelin match. FDA's December 2025 Darmerica warning letter describes firm-specific manufacturing, quality, and listing violations and says one Hexarelin acetate listing named a different active ingredient; neither record is converted here into a broader legal or product-wide conclusion.

Risks and warning limits

• human trial: Acute human studies report prolactin, ACTH, and cortisol increases; these are measured endocrine effects, not a complete adverse-event incidence profile.
• human trial: The 16-week study did not find persistent pituitary-adrenal or prolactin overstimulation under its narrow conditions, but it does not establish broad chronic safety.
• not characterized: No FDA-approved U.S. Hexarelin prescribing information was identified, so a complete labeled contraindication, warning, pregnancy, adverse-reaction, and interaction profile is not available.

What remains unknown

• Controlled human effects on strength, lean mass, fat loss, injury recovery, sleep quality, performance, and healthy longevity remain unestablished by the identified record.
• Whether acute cardiac-performance changes translate into fewer symptoms, hospitalizations, cardiovascular events, or deaths remains unknown.
• Long-term adverse effects, contraindications, pregnancy effects, immunogenicity by route, rare events, and a complete interaction profile remain incompletely characterized.

Product identity and quality limits

• FDA's Darmerica letter documents that one Hexarelin acetate listing named a different active ingredient; the finding is specific to that firm and listing.
• A GSRS identity, product name, listing, or certificate does not by itself establish the identity, form, concentration, purity, sterility, aggregation state, or stability of another material.

What has been studied together

• Naloxone and other endocrine probes — coadministration studied: Small human physiology studies coadministered Hexarelin with naloxone or other endocrine probes and measured acute hormone responses. They do not establish broad interaction safety or a therapeutic combination.
• Other drugs or peptides — no direct evidence: No adequate clinical-outcome evidence for broader consumer-style combinations was identified in the July 27, 2026 exact-substance search. Missing evidence does not establish compatibility or safety.

What people are hearing

These are claims this profile checks, not established conclusions.

• Claim under review: “Acute growth-hormone release proves Hexarelin builds muscle or speeds recovery.”
• Claim under review: “Small acute cardiac studies prove Hexarelin treats heart disease.”
• Claim under review: “A listed Hexarelin acetate product necessarily contains Hexarelin.”

Questions readers raise

• No reproducible community sample was collected for this profile.

The community-signal layer is not efficacy or safety evidence. Its current limits are:

• No reproducible community sample has been collected for this profile.
• Self-reports would be subject to selection and reporting bias.
• The identity of a product described in a self-report could not be verified.
• Concurrent medicines, behaviors, and health conditions could confound an anecdote.
• Reported outcomes could not be independently verified.
• Anecdotes cannot establish efficacy, safety, approval, product identity, or interaction compatibility.

What would change this answer

• An adequately powered controlled trial measuring patient-important body-composition, recovery, longevity, or cardiovascular outcomes with complete adverse-event reporting would change the evidence assessment.
• An exact FDA action and prescribing information would change the current U.S. status and labeled-warning boundary.
• Product-level analytical and manufacturing evidence would be required to assess another material; a shared name or listing cannot establish identity.

Sources and records

• WADA — 2026 Prohibited List

• FDA GSRS growth-hormone secretagogue substance records — U.S. Food and Drug Administration
• Darmerica LLC warning letter — U.S. Food and Drug Administration
• Drugs@FDA API exact active-ingredient search for Hexarelin — U.S. Food and Drug Administration
• ClinicalTrials.gov intervention search for Hexarelin — ClinicalTrials.gov
• PubMed Title/Abstract search for Hexarelin or examorelin — National Library of Medicine
• Growth hormone-releasing activity of Hexarelin in humans: a dose-response study — PubMed
• Effect of an opiate antagonist on hormonal changes induced by Hexarelin — PubMed
• Effect of chronic Hexarelin administration on the pituitary-adrenal axis and prolactin — PubMed
• Acute cardiovascular and hormonal effects of GH and Hexarelin in humans — PubMed
• GH-independent cardiotropic activities of Hexarelin in severe left ventricular dysfunction — PubMed
• Effects of acute Hexarelin on cardiac performance during coronary bypass surgery — PubMed
• Rapid desensitisation of the growth-hormone secretagogue receptor to Hexarelin in vitro — PubMed
• Using synchrotron radiation imaging to elucidate Hexarelin actions in small-animal hearts — PubMed