Evidence is limited to animal or in-vitro work. No human pharmacokinetics. Any human dose in circulation is extrapolated, and extrapolation across species routinely fails.
No published human half-life was located. Anti-doping work notes hexarelin is metabolised intensively and excreted as parent compound plus multiple metabolites, but reports no half-life value.
No established human therapeutic dose located. Hexarelin has been used in human endocrine research as a GH-secretagogue challenge, but a validated dosing range for repeated use is not published.
Hexarelin co-stimulates ACTH/cortisol and prolactin. It is reported to cause desensitisation of the GH response with continued administration more than other GHRPs, meaning it works less well the longer it is used. Hexarelin also binds CD36 in addition to the ghrelin receptor, giving it cardiovascular activity not shared by all GHRPs; the clinical significance in humans is not established. No long-term human safety data.