Hexarelin

Growth hormone secretagogue · Also known as Examorelin, HEX

What is hexarelin?

A synthetic six-amino acid peptide and one of the most potent growth hormone secretagogues available. It stimulates GH release through the ghrelin receptor (GHS-R1a) and has additional cardioprotective effects through the CD36 receptor.

Hexarelin was developed in the 1990s as an optimized growth hormone releasing peptide. It reached phase II clinical trials but was never approved for market due to desensitization issues with prolonged use. Research spanning three decades has also revealed cardioprotective properties independent of its GH-releasing effects.

Key takeaway: Hexarelin is one of the most potent GH-releasing peptides studied in humans, but significant desensitization occurs within 4-6 weeks of continuous use, requiring cycling.

Benefits & evidence

Growth hormone release High confidence
Cardioprotection Moderate confidence
Improved body composition Moderate confidence
Lipid metabolism improvement Preliminary confidence

How it works

Hexarelin binds to the growth hormone secretagogue receptor (GHS-R1a) on pituitary somatotroph cells, triggering a robust release of growth hormone. Its GH-releasing potency exceeds that of GHRH alone, and when combined with GHRH, the two produce a synergistic effect that is greater than the sum of their individual responses. This synergy occurs because hexarelin acts through a different signaling pathway (the ghrelin receptor) than GHRH.

Beyond GH release, hexarelin binds to CD36 receptors on cardiac tissue, producing cardioprotective effects independent of growth hormone. These include improved coronary perfusion, protection against ischemia-reperfusion injury, and anti-fibrotic effects. However, a significant limitation is receptor desensitization: GH response declines measurably by week 4 of daily use and further by week 16, though sensitivity returns to baseline after a 4-week break.

Dosing information

Typical dosing protocol
Starting dose

100 mcg/day subcutaneous

Weeks 1-2
Maintenance dose

100-200 mcg 1-3x daily subcutaneous

4-6 week cycles (break 4 weeks to resensitize)

Clinical studies used IV boluses of 1 mcg/kg. Desensitization is well-documented after 4-6 weeks of continuous use, so cycling is essential. Higher doses increase cortisol and prolactin; moderate doses (1 mcg/kg) minimize these effects. Consult a healthcare provider.

Side effects

Most side effects tend to improve as your body adjusts.

Increased appetite Common
Water retention Common
Elevated cortisol (dose-dependent) Uncommon
Elevated prolactin (dose-dependent) Uncommon
Joint and muscle pain Uncommon
Receptor desensitization with prolonged use Common

Research (10 studies)