Skip to content

GH-axis

All peptides
GH-releasing hexapeptide (GHRP)

Hexarelin

Also known as: Examorelin, His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2, EP-23905

Most potent acute GH-releaser of the classic GHRPs; cortisol and prolactin spike with sustained dosing, and tachyphylaxis builds quickly.

Reviewed 2026-05-05

What it does

Hexarelin is a synthetic 6-amino-acid growth-hormone-releasing peptide. On a per-microgram basis it's the most potent acute GH-releaser of the classic GHRPs, with consistent dose–response data in healthy adults and several disease states. Two clinical wrinkles separate it from ipamorelin and GHRP-6: a more pronounced cortisol and prolactin spike, and notable receptor desensitization (tachyphylaxis) when dosed daily for more than a couple of weeks. Preclinical work suggests possible cardioprotective effects through the ghrelin pathway independent of GH release, but no human cardiac-outcome trials have been completed.

Used for

Dose

Starting
100 mcg · 1–2× daily, cycled
Common
150 mcg · 1–2× daily, cycled
Upper
200 mcg · 1–2× daily, cycled
When
BedtimeGH secretagogue, same logic as CJC + GHRP-2. Empty stomach. Stronger pulse than ipamorelin but more receptor-downregulation risk — keep cycles short.
Site
subcutaneous

Need exact volumes? Open the peptide calculator →

⚠ Caution

  • Active malignancy (theoretical concern from GH/IGF-1 elevation)
  • Uncontrolled diabetes (insulin resistance worsens with sustained GH spikes)
  • Pregnancy and breastfeeding
  • Adolescents with open growth plates (use only under endocrinology supervision)
  • Significant baseline cortisol elevation (Cushing's, chronic prednisone) — hexarelin further raises cortisol
  • Known hypersensitivity to peptide formulations

Your stack

Track this peptide in your protocol — dose, schedule, vials on hand, refill projection. Stays in your browser; no account needed.

Add to my stack

Use this peptide

Reconstitution & storage

Lyophilized powder reconstituted with bacteriostatic water. A 5 mg vial in 2.5 mL BAC water = 2 mg/mL, making a 100 mcg dose = 5 units on a U-100 syringe. Use the Juno calculator to verify any specific vial size.

Storage. Lyophilized: refrigerate 2–8 °C. Reconstituted: refrigerate 2–8 °C, use within 30 days.

Open the peptide calculator →

Monitoring & questions

Reported side effects
  • Cortisol and prolactin elevation — more pronounced than ipamorelin, similar to or greater than GHRP-6
  • Mild appetite stimulation (less than GHRP-6, more than ipamorelin)
  • Lethargy, transient flushing, or sweating shortly after injection
  • Tachyphylaxis: GH response attenuates with continuous daily dosing beyond ~2–3 weeks
  • Water retention, mild puffiness
  • Numbness or tingling with chronic high-dose use (consistent with the IGF-1 carpal-tunnel-like syndrome of GH excess)
Biomarkers Juno tracks

Reference

How it works

Agonist at the growth hormone secretagogue receptor (GHSR-1a) at the pituitary and hypothalamus, driving pulsatile GH release. Synergizes with GHRH and GHRH analogs (CJC-1295). Independent binding to a separate cardiac receptor (CD36) has been described and underpins the proposed cardioprotective effects in animal myocardium. Sustained daily exposure downregulates GHSR-1a signaling, attenuating GH response within ~2–3 weeks of continuous dosing.

Juno's take

Hexarelin is the "most potent on paper" GHRP, but the cortisol/prolactin profile and the tachyphylaxis make it a poor daily-driver compared to ipamorelin or MK-677. The cardioprotective story is real preclinically but unconverted to human clinical outcomes — interesting biology, not clinical evidence.

EvidenceTier 2 — Human observational

Tiers are per indication. The same molecule can be Tier 1 for one use and Tier 4 for another — the tier reflects published literature, not community framing.

Stimulation of endogenous GH release

Tier 2high confidence

Multiple human pharmacology studies (Imbimbo 1994, Ghigo 1994, Massoud 1996) consistently demonstrate acute GH release after SubQ or IV administration, with hexarelin showing the largest acute peak among the classic GHRPs at equivalent doses. Tier 2 because the indication is biochemical and the studies are short-duration, small-cohort.

Imbimbo BP et al. 1994Massoud AF et al. 1996

Cardioprotection / post-MI cardiac function

Tier 3medium confidence

Animal myocardium and isolated-heart preparations show hexarelin attenuates ischemia-reperfusion injury, possibly via CD36 binding independent of GH release. Small early-phase human studies in chronic heart failure exist but are underpowered for clinical outcomes; no large trial has been completed.

Broglio F et al. 2002

Body composition / fat loss / muscle gain

Tier 3high confidence

Mechanism-as-evidence reasoning from acute GH release. No directly designed RCT in healthy adults using body composition or strength as a primary endpoint. Confounded by tachyphylaxis.

No primary citations are anchored to this indication — the tier reflects the absence of usable literature, not a missing reference.

Citations (3)
  1. [1]
    Pharmacokinetics and pharmacodynamics of hexarelin, a new growth hormone-releasing peptide, after intravenous, subcutaneous, intranasal, and oral administration in man
    Imbimbo BP, Mant T, Edwards M, et al. · European Journal of Clinical Pharmacology · 1994 · PMID 8200953
    Foundational human PK/PD characterization of hexarelin across IV/SubQ/intranasal/oral; anchors the SubQ dose range and routes.
    View source
  2. [2]
    The effect of repeated administration of hexarelin, a growth hormone releasing peptide, and growth hormone releasing hormone on growth hormone responsiveness
    Massoud AF, Hindmarsh PC, Brook CG. · Clinical Endocrinology · 1996 · PMID 8772586
    Human study characterizing tachyphylaxis with repeated dosing — direct evidence that daily continuous dosing attenuates GH response.
    View source
  3. [3]
    Effects of hexarelin on the cardiovascular system: a review
    Broglio F, Benso A, Gottero C, et al. · Cardiovascular Drug Reviews · 2002 · PMID 12466369
    Cross-trial review of hexarelin cardiovascular effects, including the GH-independent CD36-mediated cardiac actions; anchors Tier 3 cardioprotection.
    View source