Hexarelin

Grade B: Human evidence, not approved for this use

TL;DR: Hexarelin is a synthetic hexapeptide GH secretagogue studied in human trials from the early 1990s onward. A double-blind, placebo-controlled dose-response study in 12 healthy adult male volunteers (PMID 7957536, 1994) confirmed dose-dependent GH release, with peak plasma GH reaching approximately 55 ng/mL at the highest dose tested. Subsequent human research documented progressive GH response attenuation with repeated administration: a 16-week study in 12 healthy elderly subjects found that the GH area-under-the-curve declined significantly from baseline by weeks 4 and 16, though the effect was partially reversible after a washout period. Cardiovascular effects have been characterized in a controlled study of 24 male patients with coronary artery disease undergoing bypass surgery (PMID 12144941), where acute intravenous hexarelin increased left ventricular ejection fraction and cardiac output through a GH-independent mechanism attributed to myocardial GHS-R1a and CD36 receptor activation. Hexarelin has not advanced beyond Phase II development and has never received FDA approval for any indication.

Key Takeaways

Grade B: Human evidence, not approved for this use
Not FDA approved: Not FDA-approved for any indication; no IND active; not on the 503A or 503B bulk drug substances lists as of June 2026.
Compounding: Its federal compounding status is not separately established in the FDA bulk-substance lists we verify; confirm current status with a licensed pharmacist or physician before any use.

Hexarelin chemical structure — Structure via PubChem CID 6918297

Mechanism

Hexarelin binds the GH secretagogue receptor (GHS-R1a) in the pituitary and hypothalamus to stimulate pulsatile GH release, and separately activates GHS-R1a and CD36 receptors in cardiac tissue to exert GH-independent positive inotropic effects.

Evidence

Hexarelin is a synthetic hexapeptide GH secretagogue studied in human trials from the early 1990s onward. A double-blind, placebo-controlled dose-response study in 12 healthy adult male volunteers (PMID 7957536, 1994) confirmed dose-dependent GH release, with peak plasma GH reaching approximately 55 ng/mL at the highest dose tested. Subsequent human research documented progressive GH response attenuation with repeated administration: a 16-week study in 12 healthy elderly subjects found that the GH area-under-the-curve declined significantly from baseline by weeks 4 and 16, though the effect was partially reversible after a washout period. Cardiovascular effects have been characterized in a controlled study of 24 male patients with coronary artery disease undergoing bypass surgery (PMID 12144941), where acute intravenous hexarelin increased left ventricular ejection fraction and cardiac output through a GH-independent mechanism attributed to myocardial GHS-R1a and CD36 receptor activation. Hexarelin has not advanced beyond Phase II development and has never received FDA approval for any indication.

Safety and risks

The most clinically significant limitation of chronic hexarelin use is rapid receptor desensitization and tachyphylaxis: GH response declines substantially within one to two weeks of daily administration, with progressive blunting documented across 16 weeks of twice-daily dosing in human subjects; this effect is only partially reversible. Hexarelin produces dose-dependent cortisol and prolactin elevation in humans, though these transient rises normalize on discontinuation. The GH-independent positive inotropic effects documented in cardiac patients indicate direct cardiovascular pharmacological activity that could pose risks in individuals with pre-existing structural heart disease, arrhythmia, or undiagnosed cardiac conditions. Chronic elevation of GH and IGF-1 carries a theoretical cell-proliferation concern, and use is contraindicated in individuals with active malignancy or high cancer risk. No long-term controlled human safety data beyond 16 weeks exist. Compounded hexarelin carries immunogenicity risk inherent to peptide injectables, and quality of unregulated commercial preparations is not verified.

Interactions

Concurrent use with exogenous GH or GHRH may alter the GH response; somatostatin analogs are expected to attenuate hexarelin's GH-releasing activity. Potential additive cardiovascular effects with inotropic agents or vasodilators have not been systematically studied in humans.

Compounding legality

Its federal compounding status is not separately established in the FDA bulk-substance lists we verify; confirm current status with a licensed pharmacist or physician before any use.

Sources

Hexarelin is Not FDA approved. PeptideGrids presents evidence and regulatory status for informational purposes only. We do not sell, supply, source, or help anyone obtain this compound, and we provide no dosing or administration guidance. This is not medical advice; consult a licensed clinician. Full disclaimer.

Last reviewed June 1, 2026 by PeptideGrids editorial team (independently audited).