GHRP-2 (INN: pralmorelin) is a synthetic hexapeptide growth hormone-releasing peptide, CAS 158861-67-7, molecular formula C45H55N9O6, molecular weight approximately 817.98 g/mol.
It is one of the original growth hormone-releasing peptides developed as ghrelin-receptor research tools, and unlike most peptides in this catalogue it has an actual clinical history: pralmorelin is approved in Japan as a diagnostic agent used in the GH-stimulation test for suspected growth hormone deficiency, which is part of why its pharmacology is comparatively well characterised in the published literature.
Research context
GHRP-2 is a full agonist at GHS-R1a, the ghrelin/growth hormone secretagogue receptor, on pituitary somatotrophs — receptor activation triggers a pulsatile release of growth hormone that is the basis for its use in both diagnostic and preclinical research settings. Because GHS-R1a is the same receptor ghrelin itself activates, GHRP-2 also produces the orexigenic (appetite-stimulating) effects associated with the ghrelin pathway, and published studies on GHRP-2 frequently report this alongside its GH-releasing activity.
Compared to ipamorelin, GHRP-2 is less receptor-selective — study designs typically report some co-release of cortisol, prolactin and ACTH alongside the GH pulse, though generally less pronounced than with hexarelin. This intermediate selectivity profile, combined with its diagnostic-agent history, is why GHRP-2 is often used as a reference compound when comparing newer, more selective secretagogues in the literature.
Specification
CAS 158861-67-7. Molecular formula C45H55N9O6, molecular weight approximately 817.98 g/mol. Supplied as a white lyophilized powder, 10mg per vial. Batch purity to be confirmed against the Certificate of Analysis supplied with your vial.
Handling
Reconstitute with bacteriostatic water, introducing the diluent slowly against the vial wall and swirling gently rather than shaking. Store lyophilized at −20°C protected from light; refrigerate at 2–8°C once reconstituted and avoid repeated freeze-thaw cycles.
Ships with a batch-specific Certificate of Analysis. Cross-check the batch ID printed on your vial against the CoA before use — see the guide to reading a CoA if you are unfamiliar with the format.
Frequently asked questions about GHRP-2
Is GHRP-2 the same as pralmorelin?
Yes — pralmorelin is the INN (international nonproprietary name) for the same hexapeptide sold in the peptide-research market as GHRP-2. The clinical/diagnostic literature generally uses “pralmorelin,” while peptide-supplier and preclinical-research sources generally use “GHRP-2.”
How does GHRP-2 compare to GHRP-6 and hexarelin?
All three are GHS-R1a agonists from the same family. GHRP-2 sits between the two on both potency and selectivity: it is generally reported as more potent than GHRP-6 but less potent than hexarelin at the pituitary receptor, and as more selective than hexarelin but less selective than newer secretagogues such as ipamorelin.
Why does GHRP-2 affect appetite?
GHS-R1a, the receptor GHRP-2 activates, is the same receptor endogenous ghrelin binds to regulate hunger. Because GHRP-2 is a direct agonist at this receptor, orexigenic (appetite-stimulating) effects are a well-documented pharmacological property reported alongside its GH-releasing activity, not a separate or unrelated action.
Why is GHRP-2 used as a diagnostic agent?
Its reliable, dose-dependent GH-releasing activity made it useful as a provocative test agent for identifying growth hormone deficiency — a patient’s GH response to a standardised GHRP-2 dose is compared against reference ranges. This diagnostic-agent history is separate from its use as a research tool in preclinical GH-axis studies.
Research use only. Not for human or veterinary use, not for use in diagnostic procedures, and not evaluated by the U.S. Food and Drug Administration.
