Overview
Following subcutaneous administration, hexarelin is rapidly absorbed with a Tmax of approximately 15–30 minutes. It binds GHS-R1a with greater affinity than GHRP-6 but with somewhat lower selectivity, resulting in concurrent elevation of GH, cortisol, and prolactin. Peak serum GH typically reaches 40–80 ng/mL in healthy adults (dose-dependent), compared to 15–30 ng/mL for GHRP-6 and 5–15 ng/mL for ipamorelin at equivalent doses. The downstream IGF-1 rise is measurable within 24–72 hours of repeated dosing. At the cardiac level, hexarelin has demonstrated efficacy in rodent models of dilated cardiomyopathy and ischemia-reperfusion injury by attenuating mitochondrial cytochrome c release and reducing caspase-3 activation.
Proposed mechanism
Hexarelin binds to the growth hormone secretagogue receptor 1a (GHS-R1a) in the pituitary and hypothalamus, stimulating a robust release of endogenous growth hormone via activation of Gq/11 protein-coupled signaling and subsequent phospholipase C activation, leading to IP3-mediated calcium mobilization. It also activates CD36 scavenger receptors in cardiac tissue, producing GH-independent cardioprotective effects including reduced cardiomyocyte apoptosis and improved ventricular function. Additionally, hexarelin modulates cortistatin and somatostatin pathways to amplify net GH pulse amplitude.
What the evidence supports
Human data exists but the trials are small, short-term, or not yet replicated.
Graded Human-limited
Human data that exists but is thin: open-label work, single-arm studies, small cohorts, or observational follow-up without randomisation.
Key citations
Representative primary sources, including results that did not favour the compound.
- [1]
Growth hormone-releasing activity of hexarelin, a new synthetic hexapeptide, after intravenous, subcutaneous, intranasal, and oral administration in man
· Journal of Clinical Endocrinology & Metabolism, Ghigo E, et al. 79(3):666-669 · 1994
- [2]
Hexarelin, a synthetic growth hormone-releasing peptide, acts on the hypothalamus as well as the pituitary in normal subjects
· Journal of Clinical Endocrinology & Metabolism, Arvat E, et al. · 1996
- [3]
Cardiovascular actions of growth hormone secretagogues
· Journal of Clinical Endocrinology & Metabolism, Broglio F, et al. · 1999
- [4]
Hexarelin, a growth hormone-releasing peptide, protects cardiomyocytes from apoptosis
· Endocrine, Torsello A, et al. · 2001
- [5]
The GH secretagogue hexarelin stimulates the hypothalamo-pituitary-adrenal axis via arginine vasopressin
· Endocrinology, Maccario M, et al. · 1998
Citation records in this build are illustrative placeholders for the design.
Reference information for research purposes. Not medical advice, and not a recommendation to use any compound. Many entries describe substances that are not approved for human use.