GHRP-1 vs GHRP-6
The prototype versus the one that actually got studied. Both are early ghrelin-receptor peptides; GHRP-6 has far more human pharmacology and a defining appetite effect.
GHRP-1
The original GH-releasing peptide: a dose genuinely triggers a GH pulse, but that pulse is a surrogate marker — not a proven body-composition or longevity outcome — and it is unapproved.
Full GHRP-1 evidence reviewGHRP-6
Pulses GH short-term, but its most reliable real-world effect is a surge in appetite; no long-term human outcomes and not approved.
Full GHRP-6 evidence reviewSide by side
| GHRP-1 | GHRP-6 | |
|---|---|---|
| Marketed for | GH boost, 'anti-aging' | Muscle, recovery, 'anti-aging' |
| Evidence grade | Clinical data | Clinical data |
| Family | GH axis | GH axis |
| Regulatory status | Not FDA-approved | Not FDA-approved |
| How it's obtained | Research-only | Research-only |
| Key human source | Laron, Acta Endocrinol 1993 | Jaffe, JCEM 1993 |
marks a row where the two differ. Evidence grades come from our evidence matrix, which grades each molecule on the human data for the use it is marketed for.
Our verdict
GHRP-1 does what its class does: an intravenous bolus produced a progressive rise in plasma GH peaking within about 15 to 30 minutes in healthy children and adolescents, with a larger response in pubertal than prepubertal subjects. GHRP-6 has broader human characterization, with GH release documented across intravenous, subcutaneous, intranasal and oral routes, plus a strong dose-dependent appetite effect and a measurable rise in ACTH and cortisol. Both stop at the surrogate marker; there are no long-term human outcome trials behind the fat-loss, muscle or anti-aging claims for either. Neither is approved, both are research-only, and both are prohibited in sport.
GHRP-1 fits if
GHRP-1 is mostly of historical interest, relevant to a reader tracing where this peptide family started; almost everything specific about GHRP dosing and side effects comes from its descendants.
GHRP-6 fits if
GHRP-6 is the more informative read, since its human pharmacology is broader and its appetite effect is the clearest signal it reliably produces.
Where to get it
Where to get peptide therapy
Clinician-led telehealth services that prescribe compounded peptides. The specific peptides offered vary by provider — confirm GHRP-1 availability before ordering.
