Hexarelin
The most potent growth hormone secretagogue in the GHRP class, with a unique CD36-mediated cardioprotective mechanism separate from its GH-releasing activity.
Hexarelin is a synthetic hexapeptide ghrelin receptor (GHS-R1a) agonist that produces the strongest single-dose growth hormone release of any peptide in the GHRP class, meaningfully exceeding GHRP-2, GHRP-6, and ipamorelin at equivalent molar doses. Unlike other GHRPs, it also binds the CD36 scavenger receptor on cardiac tissue to produce direct cardioprotective effects independent of the GH axis. Its potency comes with a tradeoff: hexarelin drives the most pronounced cortisol, prolactin, and ACTH elevation of any commonly used secretagogue and desensitizes its receptor faster than selective peptides, which is why research protocols favor short cycles. It is not approved for any medical indication anywhere and is sold strictly as a research-use-only compound.
Class
Synthetic hexapeptide GH secretagogue (GHRP-class ghrelin receptor agonist)
Half-life
~30-70 minutes (sources report ~30-60 min and ~70 min)
Routes
Subcutaneous, Intramuscular, Intravenous (diagnostic testing only)
Category
Growth Hormone & Performance
Researched benefits
What it's studied for
Maximum GH pulse amplitude
Hexarelin produces the strongest single-dose GH response of any GHRP, with peak GH elevations of 50-100+ ng/mL achievable from modest 1-2 mcg/kg IV bolus doses. Human endocrine studies confirm it generates significantly greater GH secretion than GHRH alone.
Synergy with GHRH
Combined with GHRH analogs such as sermorelin or CJC-1295 (no-DAC), hexarelin produces 3-5x GH pulse amplification versus either compound alone by simultaneously engaging GHRP and GHRH receptor pathways while partially suppressing somatostatin.
Cardioprotective CD36 activity
Unique among GHRPs, hexarelin binds the CD36 scavenger receptor on cardiomyocytes to produce direct cardiac effects independent of the GH axis. Preclinical models document reduced infarct size after ischemia-reperfusion, improved contractility, and favorable post-MI remodeling.
Muscle recovery and lean mass support
Through robust endogenous GH and downstream IGF-1 elevation, hexarelin is researched in muscle recovery and body composition contexts, typically as a short intensive anabolic intensification tool rather than a continuous compound.
Reliable diagnostic GH stimulation
In European clinical trials, single IV boluses of hexarelin produced reliable and discriminating GH responses, making it a useful research tool for characterizing the GH secretagogue receptor system and diagnostic GH-deficiency testing.
Mechanism
How it works
Hexarelin's primary action is at the ghrelin receptor (GHS-R1a) on pituitary somatotrophs and hypothalamic neurons. Receptor binding couples through Gq/11 to phospholipase C, driving IP3/calcium release and GH granule exocytosis. It simultaneously activates the hypothalamic arcuate nucleus to amplify endogenous GHRH and partially antagonizes somatostatin, removing the ceiling on GH release. A 2-methyl-substituted tryptophan at position 2 gives hexarelin markedly higher GH-releasing potency per molecule than GHRP-2 or GHRP-6.
The same 2-methyl-tryptophan modification that amplifies GH potency also increases binding at pituitary corticotroph receptors, producing the most pronounced HPA-axis cross-reactivity in the GHRP class: cortisol elevations of roughly +30-50% above baseline in the 60-90 minute post-injection window, meaningful ACTH stimulation, and pronounced prolactin elevation. This is the fundamental tradeoff of hexarelin's potency and the reason more selective peptides like ipamorelin are preferred for clean, chronic GH support.
Separately, hexarelin binds CD36, a scavenger receptor expressed on cardiomyocytes, macrophages, and vascular endothelium. This pathway is mechanistically independent of GHS-R1a and the GH/IGF-1 axis: hexarelin produces cardiac protection even when co-administered with GHS-R1a antagonists that block GH release. CD36 engagement drives the reduced infarct size, improved ventricular contractility, anti-inflammatory endothelial effects, and favorable cardiac remodeling seen in preclinical models.
Pharmacodynamically, hexarelin desensitizes the GHS-R1a receptor faster than GHRP-2, GHRP-6, or ipamorelin. Clinical data document measurable attenuation of the GH response within 4-8 weeks of continuous daily dosing, and repeated closely spaced dosing progressively blunts the synergistic response with GHRH. This desensitization profile drives the shorter cycling recommendations that distinguish hexarelin from other secretagogues.
Dosing protocols
Dosing & administration
Dosing reflects protocols reported in research and community literature for educational purposes. It is not medical advice or a recommendation. Most peptides here are not approved for human use.
Reconstitution
Hexarelin ships as a white lyophilized powder in 2 mg, 5 mg, or 10 mg vials. A standard reconstitution is 5 mg powder + 2 mL bacteriostatic water = 2.5 mg/mL, where a 100 mcg dose = 0.04 mL = 4 units on a U-100 insulin syringe (150 mcg = 6 units, 200 mcg = 8 units). Direct the water down the glass wall rather than onto the powder cake, do not shake (gently swirl 30-60 seconds), and confirm a clear colorless solution. Store lyophilized at 2-8C (stable up to 2 years) and reconstituted at 2-8C using within 30 days; never freeze and protect from light.
Beginner
- Dose
- 100 mcg per injection
- Frequency
- 1-2x daily
- Timing
- Fasted (2-3 hours after last meal), pre-breakfast and/or pre-bed
- Duration
- 4-6 weeks on, then 2-4 weeks off
- Route
- Subcutaneous
Start pre-bed only to assess tolerance before escalating. Never continuous use without cycling. Run baseline IGF-1, cortisol, and prolactin labs.
Intermediate
- Dose
- 150-200 mcg per injection
- Frequency
- 2x daily (pre-breakfast + pre-bed)
- Timing
- Fasted
- Duration
- 4-6 weeks on / 2-4 weeks off
- Route
- Subcutaneous
Often paired with a GHRH analog in the same syringe for synergistic GH pulses. Recheck IGF-1, cortisol, and prolactin at week 4.
Advanced
- Dose
- 200 mcg per injection
- Frequency
- 2-3x daily
- Timing
- Fasted
- Duration
- 4-6 weeks on / 2-4 weeks off
- Route
- Subcutaneous
Positioned as a situational short anabolic intensification tool, commonly stacked with CJC-1295 no-DAC, testosterone (if applicable), and tissue-repair peptides. 200 mcg per injection is the practical ceiling; above it, receptor saturation prevents added GH while cortisol keeps rising.
Diagnostic (IV)
- Dose
- 1-2 mcg/kg
- Frequency
- Single bolus
- Timing
- Clinical testing setting
- Duration
- Single administration
- Route
- Intravenous
IV route reserved for diagnostic GH-stimulation testing; not a therapeutic protocol.
- Cycle shorter than other GHRPs: 4-6 weeks on, not 12+ weeks, because of faster GHS-R1a desensitization. Do not use continuously beyond 8 weeks.
- Dose fasted, 2-3 hours after the last meal minimum, because elevated glucose and insulin blunt GH release via increased somatostatin tone.
- Monitor cortisol and prolactin specifically for hexarelin. If cortisol rises >30% above baseline at follow-up, shorten the cycle, reduce dose, or take a 4-6 week washout and consider transitioning to ipamorelin.
- A common pattern is a short intensive hexarelin+GHRH phase followed by washout and maintenance with ipamorelin + CJC-1295 no-DAC.
- Mild stinging at the injection site is occasionally reported and relates to peptide acidity; persistent or severe stinging suggests stale BAC water or a vial past 30 days post-reconstitution.
Evidence
Research & clinical studies (2)
Endocrine activities of ghrelin, a natural growth hormone secretagogue (GHS), in humans: comparison and interactions with hexarelin, a nonnatural peptidyl GHS, and GH-releasing hormone
In healthy men (n=7), hexarelin produced significantly greater GH secretion than GHRH alone and synergistic GH release when combined with GHRH, while also stimulating prolactin, ACTH, and cortisol, establishing its profile as a potent non-natural GH secretagogue.
PMID 11238504The effect of repeated administration of hexarelin, a growth hormone releasing peptide, and growth hormone releasing hormone on growth hormone responsivity
In a randomized crossover trial in healthy men (n=6), hexarelin produced greater peak GH secretion than GHRH alone with synergism on initial dosing, but the synergism was attenuated with repeated dosing at 120-minute intervals, characterizing desensitization kinetics relevant to dosing design.
PMID 8762732Combinations
Stacking & blends
Hexarelin + Mod GRF 1-29 (Anabolic GH Amplification)
Maximize GH secretion for muscle growth and fat loss during a short intensive phase
Pairs the most potent GHRP with a truncated GHRH analog that provides pulsatile GH stimulation without pituitary desensitization; the complementary GHRP and GHRH receptor activation produces the largest GH pulse amplitude of any common peptide combination (3-5x versus either alone).
Hexarelin + GHRH analog (Intermediate synergy stack)
Synergistic GH pulse amplification for a 4-6 week intensive phase
Hexarelin 150-200 mcg drawn into the same syringe with sermorelin 200-300 mcg, CJC-1295 no-DAC 100-150 mcg, or tesamorelin 1 mg (if VAT reduction is also desired) produces peak GH pulses; used short-term because it also produces the highest cumulative cortisol and prolactin exposure.
Hexarelin + tissue repair
Support connective and soft tissue during aggressive training cycles
BPC-157 (~500 mcg BID) and TB-500 (2-2.5 mg twice weekly) work through distinct repair pathways that do not overlap with the GH axis, making them a safe complement during a hexarelin anabolic phase.
Safety
Side effects & considerations
Commonly reported effects
Contraindications & cautions
- Active malignancy, particularly hormone-responsive cancers
- Acromegaly
- Clinically significant hyperprolactinemia or prolactinoma
- Active Cushing's syndrome or elevated baseline cortisol
- Pregnancy and lactation
- Known hypersensitivity to hexarelin or related hexapeptides
- Severe untreated obstructive sleep apnea (stabilize with CPAP first)
- Acute critical illness (sepsis, post-surgical recovery, major trauma, respiratory failure)
- Diabetic ketoacidosis or severe uncontrolled diabetes
- Active proliferative retinopathy
- Untreated adrenal insufficiency
- Active anxiety disorder, panic disorder, or acute stress reaction
- Uncontrolled cardiovascular disease (clinical cardiac use not validated)
The HPA-axis cross-reactivity (cortisol, ACTH, and prolactin elevation) is hexarelin's distinguishing safety concern and the reason it is the least suitable GHRP for chronic daily use. Discontinuation triggers include cortisol elevation >30% above baseline, ACTH or prolactin above reference range, new or worsened anxiety/insomnia/mood changes, fasting glucose persistently >110 mg/dL, central weight gain suggesting cortisol-driven body composition change, persistent joint pain or edema, worsening sleep apnea, or any cardiovascular symptoms. Users with anxiety, HPA dysregulation, or prolactin sensitivity should choose ipamorelin instead. Avoid combining with other GHS-R1a agonists (redundant), glucocorticoids, high-dose stimulants, or GLP-1 agonists during active weight loss.
FAQ
Hexarelin — common questions
What is hexarelin and how does it work?
Hexarelin (also called examorelin) is a potent synthetic hexapeptide GH secretagogue that binds two distinct receptors: GHS-R1a, the ghrelin receptor that drives endogenous GH release, and CD36, a scavenger receptor on cardiomyocytes that drives cardioprotective effects. It is the most potent of the classical GHRPs on a per-molecule basis, producing the highest peak GH pulse at equivalent doses, but with the strongest HPA-axis cross-reactivity and fastest receptor desensitization in its class.
How is hexarelin different from GHRP-2 or ipamorelin?
All three are GHS-R1a agonists but with different selectivity. Hexarelin has the highest GH-release potency but the highest cortisol (+30-50%), ACTH, and prolactin elevation, plus the fastest desensitization. GHRP-2 offers strong potency with modest HPA effects; ipamorelin offers good potency with negligible cortisol/prolactin/ACTH impact. Hexarelin is also uniquely able to bind CD36 for cardioprotective research, which the others do not share.
What is the typical hexarelin dosage?
A standard subcutaneous protocol is 100-200 mcg per injection, 1-2 times daily (pre-breakfast and pre-bed), dosed fasted and cycled 4-6 weeks on with 2-4 weeks off. Beginners start at 100 mcg once daily. The practical single-injection ceiling is about 200 mcg, above which receptor saturation prevents additional GH release while cortisol continues to rise.
Why do hexarelin cycles need to be shorter than other GHRPs?
Hexarelin desensitizes the GHS-R1a receptor faster than GHRP-2, GHRP-6, or ipamorelin, with measurable attenuation of the GH response within 4-8 weeks of continuous daily dosing. Escalating the dose to overcome this disproportionately increases cortisol and prolactin rather than restoring GH output, so cycling 4-6 weeks on and 2-4 weeks off allows the receptor to resensitize.
Does hexarelin raise cortisol a lot?
Yes. Hexarelin produces the most pronounced cortisol elevation of any commonly used secretagogue, typically +30-50% above baseline in the 60-90 minute window, versus +15-25% for GHRP-2/GHRP-6 and negligible effects for ipamorelin. It also meaningfully elevates ACTH. Cumulative chronic exposure matters most, which is why short cycles and baseline/end-of-cycle cortisol monitoring are recommended.
What are hexarelin's cardiac effects?
Hexarelin binds CD36 on cardiomyocytes and macrophages, and preclinical animal models document reduced infarct size after ischemia-reperfusion, improved contractility, anti-inflammatory endothelial effects, and favorable remodeling after experimental MI. These effects are independent of the GH/IGF-1 axis, but clinical translation to human cardiac therapy has not occurred and no validated cardiac indication exists.
Is hexarelin legal?
Hexarelin is not FDA-approved for any indication and has no approved therapeutic use anywhere. It is sold as a research-use-only compound in most jurisdictions and is on the WADA Prohibited List, so it will show up on sport drug tests. It is not approved for human consumption.
Should I use hexarelin or ipamorelin for bodybuilding?
Ipamorelin fits most bodybuilding use cases because it can be run continuously for 12+ weeks with minimal desensitization, HPA cross-reactivity, and appetite effect. Hexarelin has a legitimate role in short 4-6 week intensive anabolic phases where maximum peak GH pulse matters, typically stacked with CJC-1295 no-DAC, after which users transition back to ipamorelin for maintenance.
