Hexarelin — Potent Growth Hormone Secretagogue — Growth Hormone
Synthetic hexapeptide GHSR agonist producing potent GH release. Research peptide with some clinical trial data.
Overview
Hexarelin (Examorelin, HEX) is a synthetic hexapeptide growth hormone secretagogue that activates the growth hormone secretagogue receptor (GHSR-1a), also known as the ghrelin receptor. Developed in the 1990s, hexarelin is one of the most potent GHRPs in terms of acute GH release. In clinical studies, a single subcutaneous injection of hexarelin 1-2 mcg/kg produced GH peaks of 30-80 ng/mL within 15-30 minutes, significantly exceeding the response to GHRH alone. Unlike GHRH analogs, hexarelin acts through the ghrelin receptor pathway, which has both GH-releasing and non-GH effects including cardioprotective properties. Studies have demonstrated that hexarelin improves cardiac function in heart failure patients, protects against ischemia-reperfusion injury, and has direct cardioprotective effects mediated through cardiac GHSR-1a receptors (CD36). However, hexarelin is notable for rapid desensitization — with daily use, GH responses can diminish within 2-4 weeks, necessitating cycling or intermittent dosing. Hexarelin also causes more cortisol and prolactin elevation than ipamorelin, making ipamorelin the preferred GHRP for most optimization applications. Hexarelin has completed Phase 2 trials in GH deficiency and heart failure but has not progressed to approval.
Indications
- Investigational: GH deficiency — Phase 2
- Investigational: Heart failure (cardioprotective effects) — Phase 2
- Unapproved: GH release and body composition (research/anti-aging)
Mechanism of Action
Hexarelin activates the growth hormone secretagogue receptor (ghrelin receptor) on pituitary somatotrophs, triggering intracellular calcium release and GH secretion
Dosing
| Compound | Dose | Frequency | Notes |
|---|---|---|---|
| Hexarelin | 100-200 mcg | 1-3 times daily | Common research dose; cycle to prevent desensitization |
| Hexarelin | 1-2 mcg/kg | Once daily | Clinical trial dose range |
Evidence Grade
GRADE C
Safety & Contraindications
- Cortisol elevation — more pronounced than ipamorelin
- Prolactin elevation — monitor for symptoms
- Rapid desensitization with chronic daily use (2-4 weeks)
- Hunger stimulation (less than GHRP-6, more than ipamorelin)
- Injection site reactions
- Not FDA-approved — research peptide