GHRP-6
GHRP6
Ghrelin-receptor secretagogue that increases GH and notably stimulates appetite.
Key takeaways
- First-generation ghrelin-mimetic that amplifies pulsatile GH release.
- Defining side effect is strong hunger via ghrelin-receptor activation.
- ~1-hour half-life; reported protocols dose 100–300 mcg 2–3× daily.
- Small, older human studies exist; not an approved medication.
Overview
What it is
GHRP-6 is a first-generation growth hormone secretagogue that mimics ghrelin at the GHS-R1a receptor, amplifying GH pulses from the pituitary. Its signature trait beyond GH release is strong appetite stimulation, a direct effect of ghrelin-receptor activation.
Pharmacokinetics
The estimated half-life is roughly one hour with around 50% subcutaneous bioavailability, so reported protocols run two to three doses daily. Because it works through a different receptor than GHRH analogs, stacking the two classes gives a larger combined pulse.
What the evidence says
Human studies exist, including oral and injectable GH-response trials in children and adults, but they are small and old. GHRP-6 is not an approved medication, and community dosing is extrapolated from that limited literature.
Reported dosing protocols
Protocols reported in research literature and clinic/community use — informational context, not a dosing recommendation.
| Use case | Dose | Route | Frequency | Duration |
|---|---|---|---|---|
| GH release + appetite (community) | 100–300 mcg | SubQ | 2–3× daily | 8–12 weeks |
Pharmacokinetic summary
- Model tier
- Simple (t½ + F, Tmax estimated)
- Half-life
- 58 min
- Bioavailability
- 50%
- Typical dose
- 0.1–0.3 mg
Frequently asked questions
Why does GHRP-6 cause so much hunger?
It activates the ghrelin receptor, and ghrelin is the body's main hunger hormone. The appetite surge 20–30 minutes after injection is a direct on-target effect, not a contaminant or quirk. Users who want GH release without hunger usually switch to ipamorelin.
GHRP-6 vs ipamorelin — which is cleaner?
Ipamorelin is the selective option: strong GH release with minimal cortisol, prolactin, and hunger effects. GHRP-6 is less selective but cheaper, and its appetite stimulation is either a feature or a dealbreaker depending on the goal.
Is GHRP-6 approved or legal?
It is not an approved medication anywhere. Small human studies ran in the 1990s, but no therapeutic development followed. Material sold today is research-grade, and WADA prohibits it in tested sport.
References
- Estimated — Ghrelin-mimetic secretagogue; notable appetite stimulation.
- Eur J Endocrinol 1995 — oral GHRP-6 GH response in children — Human study showing GH release after oral GHRP-6 in short-stature children.
Related compounds
Ipamorelin
Selective GHRP secretagogue releasing growth hormone with relatively minimal cortisol/prolactin effect.
GHRP-2
Growth hormone secretagogue that acts on the ghrelin receptor to amplify GH pulses.
MK-677 (Ibutamoren)
Orally active growth hormone secretagogue (ghrelin receptor agonist) that elevates GH and IGF-1; the non-peptide counterpart to injectable GHRPs.
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