The older-generation GHRPs — GHRP-2 is the pharma-developed version (pralmorelin), GHRP-6 is the hunger-inducing outlier. Both have largely been replaced by ipamorelin in modern protocols.
GHRP-2 (pralmorelin) and GHRP-6 are synthetic hexapeptides developed in the 1980s–1990s as growth hormone secretagogues. Both activate the ghrelin receptor to trigger GH release from the pituitary, but with different secondary profiles:
GHRP-2 was advanced to clinical trials (under the name pralmorelin) in Japan but never fully commercialized. Both are now primarily research chemicals.
Not FDA approved. WADA prohibited (S2). Pralmorelin is still used as a diagnostic agent for GH deficiency in Japan.
Both bind GHS-R1a to trigger GH release. Potency: hexarelin > GHRP-6 ≥ GHRP-2 > ipamorelin. All produce a GH pulse; selectivity and side-effect profile differ.
GHRP-6 is a stronger functional ghrelin mimetic in the hypothalamic hunger circuit than its peers. Historically used for underweight cachectic patients — now avoided by most users who don’t want the appetite boost.
Both raise these modestly — less than hexarelin, more than ipamorelin. The main reason both have lost ground to ipamorelin over the last decade.
| Benefit | Evidence |
|---|---|
| GH elevation | Both produce reliable GH pulses; GHRP-2 slightly larger than GHRP-6 in head-to-head studies |
| Appetite stimulation | GHRP-6 meaningful; GHRP-2 modest. Useful for hard-gainers / underweight patients |
| Body composition | Modest lean mass gains + fat loss over 8–12 weeks |
| Sleep | Pre-bed dose supports slow-wave sleep |
| Diagnostic use (GHRP-2) | Pralmorelin approved in Japan as a GH-deficiency diagnostic agent |
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Start Tracking Free100 mcg is the commonly cited saturation dose in practitioner protocols — more is reported to produce more side effects rather than a bigger GH pulse. Note that PMID 9285939 tested GHRP-2 at 1–2 mcg/kg IV in adults (~70–140 mcg range) and showed dose-dependent GH responses across that range, so the saturation point is approximate and may vary with body weight. Scale number of pulses per day (up to 3), not per-dose, if you want more total GH exposure.
GHRP + GHRH synergy applies here too. GHRP-2 + CJC-1295 or + sermorelin produces a larger pulse than either alone. Most users who want this stack use ipamorelin instead for the cleaner profile.
5 mg vial + 2.5 mL BAC water = 2000 mcg/mL
| Dose | Volume | Syringe Units |
|---|---|---|
| 100 mcg | 0.05 mL | 5 units |
| 150 mcg | 0.075 mL | 7.5 units |
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GHRP-2 and GHRP-6 is a research peptide not approved by the FDA for human use. It is sold only as a research chemical, and StackTrax does not endorse or facilitate personal use.
Quality varies enormously among research-chemical suppliers. At minimum, look for:
StackTrax’s preferred partner NextGen Peptides does not currently carry GHRP-2 and GHRP-6in their catalog, which is why you don’t see a direct purchase link here. Other major research-chemical suppliers carry it; we don’t specifically recommend one for this compound.
Build your protocol, log every dose, monitor your body's response, and get reminders so you never miss a dose.
Start Tracking FreeDisclaimer: This guide is for educational and informational purposes only and is not intended as medical advice, diagnosis, or treatment. The compounds discussed are not FDA approved for human use. Always consult a qualified healthcare provider before starting any new supplement or peptide protocol. StackTrax does not sell peptides or supplements directly — purchase links go to third-party vendors. StackTrax is not responsible for the products, quality, or business practices of any third-party vendor. This page contains affiliate links — StackTrax may earn a commission on purchases at no extra cost to you.
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StackTrax guides cover peptides and compounds that are not FDA-approved for the uses discussed. The dosing, reconstitution, and safety information is compiled from published research and community protocols for educational purposes only.
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