Cite this answer
GHRP-2: quick citable summary
GHRP-2 is listed by PeptaHub as a muscle & growth peptide with a research only legal-status classification. The page summarizes mechanism, research context, common routes, safety notes, and references for writers and AI answer engines.
PeptaHub. “GHRP-2: Mechanism, Research Context, Safety.” peptahub.com, 2026. https://peptahub.com/peptides/ghrp-2. Licensed CC BY 4.0.
License: Creative Commons Attribution 4.0 International. Link back to https://peptahub.com/peptides/ghrp-2.
What is GHRP-2?
GHRP-2 (Pralmorelin) is a potent growth hormone releasing peptide approved in Japan as a diagnostic agent for GH deficiency. It stimulates GH release via the ghrelin receptor with moderate appetite and cortisol effects, sitting between Ipamorelin and GHRP-6 in side effect profile.
Overview
GHRP-2 (Pralmorelin) is a synthetic hexapeptide ghrelin receptor agonist and potent growth hormone secretagogue. Approved in Japan as a diagnostic agent for GH deficiency, it is the most selective of the first-generation GHRPs, producing strong GH release with less appetite stimulation than GHRP-6 and lower cortisol/prolactin elevation than other peptides in its class.
Mechanism of action
GHRP-2 acts as a selective agonist at the ghrelin receptor (GHSR-1a) in the pituitary and hypothalamus. Binding triggers calcium mobilization and protein kinase C activation, resulting in pulsatile GH release from somatotroph cells. Simultaneously, GHRP-2 suppresses somatostatin tone, which normally inhibits GH secretion, thereby amplifying net GH output. It also activates hypothalamic neuropeptide Y (NPY) neurons, contributing to mild appetite stimulation — though this effect is significantly less pronounced than with GHRP-6. At standard doses GHRP-2 produces modest cortisol and prolactin elevation, which some users manage by pairing it with a GHRH analog. Its terminal plasma half-life was about 33 minutes in a phase I study in children (Pihoker, JCEM 1998), so community protocols use multiple daily injections to maintain elevated GH pulsatility.
Reported study ranges
| Purpose | Route | Reported range | Frequency | Notes |
|---|---|---|---|---|
| GH secretion and body composition | subcutaneous | 100–300 mcg | 2–3 times daily | Users commonly inject 100–300 mcg per dose on an empty stomach, 3 times daily (morning, pre-workout, and pre-sleep). Often paired with a GHRH analog (CJC-1295, Mod-GRF 1-29) for synergistic effect. |
| diagnostic GH stimulation test (clinical use) | intravenous | 100–100 mcg | single dose | Japanese PMDA-approved diagnostic protocol: 100 mcg IV bolus, GH measured at 30, 60, and 90 minutes. Peak GH >16 ng/mL (children) or >9 ng/mL (adults) rules out deficiency. |
Reported ranges are for research context only. Consult a qualified healthcare professional before using any peptide.
Convert GHRP-2 research-range units
Need to convert mg to mcg, dose volume, or U-100 syringe units? The GHRP-2 dose calculator is preloaded with these ranges, or use the general dose unit converter.
Research summary
Approved in Japan as a diagnostic agent for GH deficiency assessment. The published human work is mostly acute pharmacology: a phase I study in 10 prepubertal children with short stature characterised the pharmacokinetics and a predictable GH rise after a single 1 mcg/kg intravenous dose (Pihoker, JCEM 1998), and a study in GH-deficient patients with a mutated GHRH receptor showed GHRP-2 still raised GH 4.5-fold, versus 79-fold in controls, indicating a GHRH-independent pituitary action (Gondo, JCEM 2001). In healthy men, GHRP-2 increased food intake (Laferrère, JCEM 2005). There is no published trial of long-term anabolic or body composition outcomes. Community use for muscle building and anti-aging rests on user-reported protocols, not controlled trials.[1][2][3][4][5][6]
Evidence grading
Each claimed benefit is graded by the strength of available evidence. Grades reflect study quality, not effect size.
Strong = multiple RCTs · Moderate = limited trials or observational · Preliminary = animal or in vitro only · Insufficient = anecdotal or no published data
Side effects
Side effects vary by individual. This is not an exhaustive list. Report unusual symptoms to a healthcare professional.
Common stacks
Peptides commonly paired with GHRP-2 for synergistic effects.
Legal status
GHRP-2 cannot legally be compounded in the US today. It was placed on the FDA's Category 2 bulk drug substances list in September 2023, which put it outside enforcement discretion for compounding. It was not among the 12 peptides the FDA removed from Category 2 on April 15, 2026, so it remains in Category 2, and no Pharmacy Compounding Advisory Committee review of GHRP-2 has been scheduled. This confirms what industry analysis had anticipated on the basis of cortisol and prolactin elevation concerns. GHRP-2 is approved as a diagnostic agent in Japan but is not FDA-approved in the US. Verify current federal and state rules before relying on access claims.
Sourcing & access
Research compound
GHRP-2 is classified as a research compound. Regulatory status varies by jurisdiction. Always verify current legal status and source from vendors providing third-party certificates of analysis (COA).
Frequently asked questions
GHRP-2 (Pralmorelin) is a synthetic hexapeptide that stimulates growth hormone secretion via the ghrelin receptor (GHS-R1a). It is approved in Japan as a diagnostic agent for GH deficiency testing and is widely used in the research community for body composition optimization.
GHRP-2 produces slightly less appetite stimulation than GHRP-6 while maintaining potent GH release. Both elevate cortisol and prolactin transiently. GHRP-2 is considered more selective, sitting between the clean profile of Ipamorelin and the strong appetite effects of GHRP-6.
GHRP-2 was placed on the FDA Category 2 bulk drug substance list in September 2023, banning compounding pharmacy preparation in the US. As of 2026, it is expected to remain on Category 2 due to cortisol and prolactin elevation concerns.
Research protocols commonly use 100 to 300 mcg per dose injected subcutaneously on an empty stomach, 2 to 3 times daily. It is often paired with a GHRH analog like CJC-1295 or Mod GRF 1-29 for synergistic GH release.
Side effects include mild increased appetite, transient cortisol and prolactin elevation, injection site redness, water retention, headache, and flushing. GHRP-2 clears quickly, with a terminal plasma half-life of roughly 33 minutes measured in a phase I study. The cortisol and prolactin profile is the concern most often cited for its FDA Category 2 status.
Research references
- Growth hormone-releasing peptides: clinical and basic aspectsPubMed
- Pharmacokinetics and pharmacodynamics of growth hormone-releasing peptide-2: a phase I study in childrenPubMed
- Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy menPubMed
- Growth hormone-releasing peptide-2 stimulates GH secretion in GH-deficient patients with mutated GH-releasing hormone receptorPubMed
- Clinical Usefulness of the Growth Hormone-Releasing Peptide-2 Test for Hypothalamic-Pituitary DisorderPubMed
- Two ghrelin receptor agonists for adults with malnutrition: a systematic review and meta-analysisPubMed