GHRP-6
GHRP-6 is a first-generation growth-hormone-releasing hexapeptide and ghrelin-receptor agonist. It reliably releases GH but is notable for causing strong hunger via ghrelin signalling, and it modestly raises cortisol and prolactin. Studied in older human GH-secretion trials; non-medical physique use is anecdotal.
01 Overview
GHRP-6 was one of the earliest synthetic secretagogues and helped establish the ghrelin/GHS-R pathway. It produces a robust GH pulse but its marked appetite stimulation is the defining practical feature, sometimes exploited to encourage eating but often unwanted.
It has been used in human GH-provocation studies and shares the cortisol/prolactin effects of non-selective GHRPs. For ongoing body-composition use it is largely superseded by more selective peptides. Physique efficacy is not established in controlled trials.
02 Mechanism
Agonist of the growth-hormone secretagogue receptor (GHS-R1a, ghrelin receptor), stimulating a GH pulse; strong central ghrelin-receptor activation also drives appetite, with modest ACTH/cortisol and prolactin rises.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Anecdotal (non-medical) | 100–150 mcg | SubQ | ~100-150 mcg per injection; pronounced hunger within ~30 min of dosing. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| GH releaseReliable GH pulse demonstrated in human provocation studies. | Clinical | ||
| Strong appetite stimulationPotent ghrelin-mediated hunger; useful for hard-gainers but often unwanted. | Marked hunger within ~30 min | Clinical | |
| Fat loss and recoveryReported recovery/body-composition benefits from GH elevation; not established in trials. | Anecdotal |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Intense hungerStrong, sometimes disruptive appetite after each dose. | Mild | Universal | Clinical | |
| Raised cortisol and prolactinModest ACTH/cortisol and prolactin elevation. | Moderate | Common relative to selective GHRPs | Clinical | |
| Water retention / injection-site reactionsFluid retention and local injection reactions. | Mild | Common | Anecdotal |