Hexarelin is a synthetic hexapeptide built on a growth hormone releasing peptide six scaffold. It belongs to the GHRP family alongside GHRP-2, GHRP-6, ipamorelin, the peptide mimetic MK-0677, and ghrelin itself. What distinguishes it is a dual receptor mechanism: it acts as a growth hormone secretagogue receptor 1a agonist and as a ligand at the CD36 scavenger receptor. This pairing drives both endocrine and cardiac effects, which is why hexarelin reads differently from the cleaner, more GH-selective profile of ipamorelin.

On the endocrine side, hexarelin stimulates growth hormone release from the anterior pituitary, supports growth hormone releasing hormone activity in the hypothalamus, and inhibits somatostatin at both sites. In equimolar human comparisons, growth hormone release runs roughly two times greater than the GHRH equivalent, with a clear dose-dependent response across routes.

The CD36 arm is where much of the interest sits. Through PPAR gamma and liver X receptor alpha signaling, it upregulates the ABCA1 and ABCG1 transporters that move cholesterol out of the cell back toward the liver. Preclinical models also show anti-fibrotic, anti-apoptotic, and anti-ischemic activity, including improved left ventricular ejection fraction and reduced lipid peroxidation markers in animal heart failure models.

The framework Dr. Seeds outlines aims to keep clinicians out of trouble: a subcutaneous range of roughly 50 to 100 micrograms, dosed one to three times daily, cycled twelve weeks on with four weeks off. Lower, continuous dosing is intended to limit receptor desensitization and the cortisol and prolactin elevations seen at higher doses. For greater GH release, a smaller hexarelin dose can be paired with a GHRH analog such as CJC-1295, tesamorelin, or sermorelin.

Key clinical points

• Strongest evidence is preclinical. Cardioprotective, anti-fibrotic, anti-ischemic, and positive inotropic findings come largely from animal data, with some supporting human inotropic and coronary artery disease observations.
• Tachyphylaxis is partial and reversible. Attenuated growth hormone response with chronic use can recover within about four weeks. Hexarelin carries the highest desensitization potential among the GHRPs, so cycling matters.
• Higher doses raise cortisol and prolactin. These dose-dependent elevations are a reason to favor restraint.
• No FDA approval and no completed human randomized outcome trials. Long-term safety and human cardiac outcomes remain open questions.
• Subcutaneous administration appears most efficient. Oral, intranasal, and IV routes were studied, but subcutaneous dosing was the most clinically practical.