Not approved — human endocrine activity, no established outcomes use
An experimental peptide that can cause a strong, short-term release of growth hormone.
5-minute readFull profile reviewed July 31, 2026
Evidence is explained by question. Dosing references show their own check dates.
60-second overview
Hexarelin at a glance
Why people look into it, what studies found, and what is still unknown.
Why people look into it
Hormone release, sleep, and early research on heart function.
What studies found
Small studies found increased growth hormone and changes in other hormones. Repeated use reduced the response, and one tiny study found less deep sleep.
What is still unclear
Long-term benefits and safety remain unclear. Hormone changes have not established better muscle growth, recovery, sleep, or lifespan.
About the evidence and review date
Educational information only. Evidence reviewed through July 31, 2026. Published studies, sponsor announcements, and trials without results are labeled separately. Evidence gaps apply to the specific finding beside them.
Research questions
Why people research it
Each label shows how much evidence supports that question.
Acute endogenous GH releaseSupported by human studies
Prolactin and HPA-axis effectsSupported by human studies
Repeated-exposure response attenuationEarly human evidence
Acute cardiac physiologyEarly human evidence
Muscle gain, fat loss, or recoveryNot demonstrated
Sleep improvementNot demonstrated
Human longevity or anti-agingNot demonstrated
What studies show
What the evidence supports
The research behind the answer
Multiple small controlled endocrine studies consistently demonstrate acute GH release and document prolactin, ACTH, and cortisol effects; a 16-week study showed progressive attenuation of the GH response.
See each finding and its sources (8)
Mechanistic rationale
Hexarelin is a synthetic hexapeptide growth-hormone secretagogue that activates ghrelin/GHS receptor signaling and can stimulate pituitary GH release.
It belongs to the GHRP family and is mechanistically distinct from GHRH analogs such as Sermorelin or Tesamorelin and from direct somatropin replacement.
Binding and acute endocrine activity do not establish long-term clinical benefit or a product-quality standard.
Small acute cardiac studies reported short-lived hemodynamic effects, but no long-term cardiovascular outcomes program establishes Hexarelin as a cardiac treatment.
Interesting acute physiology is not the same as fewer heart-failure events, improved survival, or durable functional benefit.
The studies involved highly selected and monitored patients, small samples, and acute endpoints.
No controlled human evidence located by Relay establishes Hexarelin for bodybuilding, muscle gain, fat loss, injury recovery, longevity, or sustained sleep improvement.
The human record is dominated by endocrine challenge studies and small acute cardiovascular experiments.
Absence of identified evidence does not prove no effect, but it prevents confident benefit or safety claims.
Relay has not verified a clear pattern of side effects for this compound.
Evidence boundary
Human exposure is present, but the record is not detailed enough to characterize a reliable adverse-event pattern.
Missing reports do not establish safety. Findings apply to the product, route, amounts, population, comparison, and follow-up studied.
Side-effect frequency, study withdrawals, and gaps
How often side effects occurred
The available information does not reliably show how often particular side effects occur.
Evidence boundary
Under-detected or under-reported events must not be described as rare.
Why people stopped in studies
Relay has not verified which side effects led people to stop treatment in studies.
Evidence boundary
This is an evidence gap, not proof that discontinuations did not occur.
Warning information
Relay has not verified a compound-specific warning summary for this profile.
Evidence boundary
Not FDA approved; no approved Hexarelin product label or modern outcomes program identified Long-term clinical benefit and safety, including repeated HPA-axis and prolactin effects, glucose and metabolic consequences, cardiovascular risk, receptor desensitization, and the quality of unapproved commercial material.
Emergency instructions
This profile does not contain verified, product-specific emergency instructions.
Evidence boundary
Relay does not infer emergency guidance from study discontinuations, mechanism, or incomplete adverse-event reporting.
Dosing references
Dosing & preparation
Each table labels its source and applies only to the named route, product, or study. An online example or community report is not an approved dose.
IV · Into a vein
Human study · source-specific regimenWhat this means
Amounts reported in a human study. A studied amount is not automatically an approved dose or a recommendation for an individual.
Hexarelin · IV single-exposure study
A 12-volunteer experiment compared hormone responses across different routes.
Amounts studied
1 or 2 micrograms/kg
Frequency
Single experimental challenges
Treatment period
Acute laboratory sessions
Hexarelin · IV single-exposure study
Stage / period
Amounts studied
Frequency
Acute experiment
1 or 2 micrograms/kg
Single challenges
These are distinct route experiments, not equivalent doses or a repeated treatment course. Hormone release does not establish long-term benefit.
This source does not establish a mixing volume or storage period for independently sourced powder. Use formulation-specific instructions; the study amount alone is not a reconstitution recipe.
Concentration = total mass ÷ final volume. The calculator performs user-entered math; it does not choose a dose or diluent.
Hexarelin is a synthetic hexapeptide in the GHRP family that activates growth-hormone-secretagogue signaling at hypothalamic and pituitary sites. Small controlled human studies demonstrate robust acute GH release, but also prolactin and hypothalamo-pituitary-adrenal activation. Repeated administration produced response attenuation in a 16-week elderly cohort, and a nocturnal placebo-controlled study reported reduced slow-wave sleep measures despite higher GH. Specialized acute cardiac studies suggested short-lived GH-independent hemodynamic effects in selected monitored patients, but no long-term cardiovascular outcomes program was identified. The record does not establish anabolic, body-composition, recovery, longevity, or sleep benefit in healthy users.
Why this matters
A plausible mechanism can explain why a study was attempted. It does not prove that the compound improves a human outcome.
Signals and targets
Growth hormone secretagogue receptor 1a (GHSR1a)Proposed peptidyl-GHS peripheral binding sitesCD36 - proposed cardiac mechanism in preclinical literature
Proposed biological steps
Growth hormone secretagogue receptor signaling
Hypothalamic and pituitary stimulation of GH release
Additional prolactin and HPA-axis activation
Proposed peripheral cardiac receptor activity
Research reference
How mature is the evidence?
A reference for the studies, populations, and routes behind this profile.
Research depthRepeated small human endocrine studies
Controlled experiments characterize acute hormone release and route effects, but clinical-outcome research is absent.
Why this matters
Research depth describes how large and mature the overall record is. It does not tell you whether the results were positive.
Evidence confidenceModerate for acute endocrine effects
Acute GH release is consistent; long-term benefit, safety, and sustained response are unresolved.
Why this matters
Confidence describes how reliable and consistent the conclusions are. It can be high for one outcome and low for another.
Strongest evidenceSmall controlled human endocrine studiesWhy this matters
The strongest evidence type shows what the best-supported conclusions are actually based on.
Human evidenceConsistent acute hormone effects; no established long-term clinical benefitWhy this matters
Human findings are more directly relevant than animal or laboratory results, but they still apply only to the populations and outcomes studied.
Route studiedIntravenous, subcutaneous, intranasal, and oral routes in separate study conditions
Schedules studiedSingle monitored exposure per condition; Single-dose test sessions
Amounts studiedWithheld: this record provides research context without a transferable amountWhy this matters
These are exposures used in cited research for a specific route and population—not an instruction for an individual.
Half-lifeNot established for this exact editorial recordWhy this matters
Half-life describes how long it takes the measured amount in the body to fall by half. It is not a dosing recommendation.
Route evidenceA small controlled human study compared several administration routes to measure acute growth-hormone release.Why this matters
Evidence can change by administration method. Findings from one route should not automatically be applied to another.
Evidence boundary: Only 12 healthy volunteers were included, and the study measured an acute hormone response. Different route conditions do not establish route equivalence, chronic benefit, a consumer schedule, or long-term safety. Amounts shown describe cited research exposure—not a dosage recommendation.
Studies
Study-by-study record
Study arms are reported for transparency. They describe what researchers did in a defined record and do not transfer across identities, routes, formulations, or populations.
Why this matters
A later trial phase can ask a more mature question, but it does not guarantee a positive result, regulatory approval, or relevance outside the studied population.
Controlled human studyPeer reviewed
Hexarelin decreases slow-wave sleep and stimulates GH, ACTH, cortisol and prolactin during sleep in healthy volunteers
Placebo-controlled overnight sleep EEG and hormone profiling
Seven healthy young volunteers
Outcomes measured
Sleep stages
EEG delta power
GH
Prolactin
ACTH
Cortisol
What was reported
Hexarelin increased several hormones but reduced stage-4 sleep and total-night delta power in this small study.
Study administration and important limits
Study administration: Four protocol-specific nocturnal hexarelin administrations or placebo
Limitations: A seven-person one-night study cannot establish chronic sleep effects, but it directly contradicts simple claims that hexarelin necessarily improves deep sleep.
Controlled human studyPeer reviewed
Impact of two or three daily subcutaneous injections of hexarelin on 24-h GH, prolactin, adrenocorticotropin and cortisol secretion in humans
Intensive 24-hour sampling after two or three subcutaneous administrations
Six healthy young men
Outcomes measured
24-hour GH
IGF-1
Prolactin
ACTH
Cortisol
Desensitization
What was reported
Two and three administrations increased 24-hour GH secretion to a similar extent. IGF-1 did not change during the one-day schedules, and a later challenge showed a blunted GH response.
Study administration and important limits
Study administration: Two or three protocol-specific subcutaneous hexarelin administrations
Limitations: One-day exposure in six men cannot establish sustained anabolic, recovery, body-composition, or safety outcomes.
Controlled human studyPeer reviewed
The growth hormone secretagogue hexarelin stimulates the hypothalamo-pituitary-adrenal axis via arginine vasopressin
Dose-response comparison with GHRH and low-dose combination testing
Healthy adult men
Outcomes measured
GH
Prolactin
Cortisol
What was reported
Hexarelin increased GH, prolactin, and cortisol in a dose-dependent pattern. Low-dose hexarelin combined with GHRH produced strong GH release with less cortisol effect in that experiment.
Study administration and important limits
Study administration: Protocol-specific intravenous hexarelin and GHRH exposures
Limitations: Small acute endocrine study. Hormone peaks are not clinical outcome evidence and do not establish a safe chronic combination strategy.
Controlled human studyPeer reviewed
Growth hormone-releasing activity of hexarelin after intravenous, subcutaneous, intranasal, and oral administration in man
Within-subject comparison of several administration routes and doses
12 healthy young volunteers
Outcomes measured
Growth hormone response
Route-dependent bioactivity
Comparison with GHRH
What was reported
Hexarelin produced strong acute GH release after intravenous and subcutaneous administration, with smaller or variable responses through other studied routes.
Study administration and important limits
Study administration: Protocol-specific intravenous, subcutaneous, intranasal, and oral hexarelin exposures; descriptive research context only
Limitations: Acute hormone release in 12 healthy volunteers does not establish long-term clinical benefit, body-composition change, recovery, muscle gain, safety, or consumer route equivalence.
Other human evidencePeer reviewed
Effects of acute hexarelin administration on cardiac performance in patients with coronary artery disease during bypass surgery
Relay did not identify a modern registered Hexarelin development program establishing long-term recovery, muscle, body-composition, sleep, or cardiovascular outcomes.
Study administration and important limits
Study administration: Not stated in the current record.
Limitations: A registry search cannot prove that no unregistered or non-U.S. study exists.
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