Compound monograph
Pralmorelin (GHRP-2)
Pralmorelin is a synthetic hexapeptide growth hormone secretagogue acting at the ghrelin receptor, containing three D-configured residues and a naphthylalanine substitution.
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Identity & nomenclature
Pralmorelin is a synthetic hexapeptide growth hormone secretagogue acting at the ghrelin receptor, containing three D-configured residues and a naphthylalanine substitution.
GHRP-2 is not GHRP-6; they are different hexapeptides. Arvat et al. (PMID 9285939) describe GHRP-2 as a synthetic super-analog of GHRP-6, although the chain printed in their abstract omits Ala3; the six-residue chain recorded here matches PubChem CID 6918245. And GHRP does not denote a GHRH-receptor ligand — the similar names refer to GH secretion, not a shared receptor. A generic 'Nal' field loses both the 2-naphthyl substitution and the D configuration, either of which changes the molecule.
Canonical name: Pralmorelin.
Declared aliases and development codes: GHRP-2, Growth hormone-releasing peptide-2, KP-102.
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Molecular properties
| Molecular formula | C45H55N9O6 |
|---|---|
| Molecular mass | 817.99 Da |
| CAS Registry Number | 158861-67-7 |
| PubChem CID | 6918245 |
| UNII | E6S6E1F19M |
| Three-letter sequence | D-Ala–D-2-Nal–Ala–Trp–D-Phe–Lys |
| Terminal groups | Free N-terminus; C-terminal amide at Lys6 |
No one-letter string is published here. Position 2 is 3-(naphthalen-2-yl)-D-alanine, a single nonstandard residue; written as ordinary letters it would denote different amino acids. Three of six residues are D-configured and the stereochemistry is identity-defining, not annotation.
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Structural characteristics
Pituitary work distinguishes its direct action from GHRH-mediated responses, and it appears in CD36 binding competition experiments alongside hexarelin. The CD36 observation is a binding result in the systems tested; it does not establish that every pralmorelin response is CD36-mediated.
- D-2-naphthylalanine at position 2
- D-Ala1
- D-Phe5
Terminal features: Free N-terminus, C-terminal amide at Lys6.
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Molecular targets & mechanisms
Growth hormone secretagogue receptor
GHS-R1a · Ghrelin receptor · GHSR
A G-protein-coupled receptor distinct from the GHRH receptor. Antagonist profiling reported that ipamorelin releases growth hormone through a GHRP-like receptor rather than through the GHRH receptor, establishing the two pathways as separate.
CD36 scavenger receptor
CD36 · FAT · SR-B2
A multifunctional scavenger receptor, distinct from the growth hormone secretagogue receptor, reported as a binding target for certain synthetic secretagogue peptides. It is recorded separately here precisely because collapsing it into the ghrelin-receptor mechanism would erase the finding that these compounds are not pharmacologically interchangeable.
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Analytical considerations
An intact-mass match distinguishes neither D from L residues nor 1-naphthyl from 2-naphthyl positional isomers — both are identical in elemental composition. Those require chiral amino-acid analysis with authentic standards, or NMR. A growth-hormone secretion assay cannot establish which GHRP is present; the comparative LC-MS work is the reference that actually separates them.
Disagreements and mix-ups
Points where sources disagree about this compound's identity, or where a name or form is easily confused with another, as noted in this record. The discrepancy register quotes the passage for each one.
Often mixed up · Registry identifier
GHRP-6 vs GHRP-2 on a PubChem record with the same formulaAlso noted in GHRP-6
Often mixed up · Name or substance
"GHRP" does not mean a GHRH-receptor ligand
What the studies reported
Each finding describes one cited study in its stated model. These observations are specific to that study and do not establish effects in other settings.
Cell and tissue studies
Ovine somatotropes
In ovine somatotropes, the study reported time-dependent increases in GH mRNA and GH release after GHRP-2 exposure from 0.5 to 2 h.
Reference [1]Ovine somatotropes
In ovine somatotropes, the study reported increased Pit-1, GHRH-R and GHS-R mRNA after 0.5 h of GHRP-2 exposure.
Reference [1]Ovine somatotropes
In ovine somatotropes, the study reported inhibited sst-1 and sst-2 mRNA expression after 0.5–2 h of GHRP-2 exposure.
Reference [1]
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Verified bibliography
Cited studies by type
The 4 papers this record cites, counted by the kind of work each reports. A count is the size of this record's selection, not of the research that exists, and says nothing about results, safety, effectiveness or approval.
A paper can report more than one kind of work. Each count opens those papers in the bibliography. Compare every record on the Evidence Map.
Reference 1
Effect of GHRH and GHRP-2 treatment in vitro on GH secretion and levels of GH, pituitary transcription factor-1, GHRH-receptor, GH-secretagogue-receptor and somatostatin receptor mRNAs in ovine pituitary cells.Yan M, Hernandez M, Xu R, Chen C
European journal of endocrinology · 2004-02 · Journal Article
currentReference 2
Identification of the growth hormone-releasing peptide binding site in CD36: a photoaffinity cross-linking study.Demers A, McNicoll N, Febbraio M, Servant M, Marleau S, Silverstein R, Ong H
The Biochemical journal · 2004-09-01 · Journal Article
currentReference 3
Determination of growth hormone releasing peptides (GHRP) and their major metabolites in human urine for doping controls by means of liquid chromatography mass spectrometry.Thomas A, Höppner S, Geyer H, Schänzer W, Petrou M, Kwiatkowska D, Pokrywka A, Thevis M
Analytical and bioanalytical chemistry · 2011-02-06 · Journal Article
currentReference 4
Effects of GHRP-2 and hexarelin, two synthetic GH-releasing peptides, on GH, prolactin, ACTH and cortisol levels in man. Comparison with the effects of GHRH, TRH and hCRH.Arvat E, di Vito L, Maccagno B, Broglio F, Boghen MF, Deghenghi R, Camanni F, Ghigo E
Peptides · 1997 · Journal Article
current
Study models of these references
What kind of experiment each cited paper reports, taken from its abstract unless marked. Not a summary of results.
| Reference | Study models |
|---|---|
| Yan M et al. 2004 | Study models reported: in vitro · from the abstract |
| Demers A et al. 2004 | Study models reported: in vitro · from the abstract |
| Thomas A et al. 2011 | Study models reported: in vitro · from the abstract |
| Arvat E et al. 1997 | Study models reported: human participants (interventional) · from the abstract |
Record history
Published 2026-09-13.
- : Sequence and structure
- : Identity and nomenclature, References
Each entry names the parts of this record that changed on that date. Changes to links between records and to catalogue links are not listed. This history covers the tracked record fields; study findings are not listed here.
Cite this record: Purely Peptides Research Library. Pralmorelin (GHRP-2). Published 2026-09-13; updated 2026-10-15. https://purelypeptides.org/research/compounds/pralmorelin/
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Methodology & citation verification
Reference identity is checked against official PubMed metadata. Local deterministic receipts bind each normalized title and canonical metadata record to its verification date. Scientific values remain absent when an authoritative source has not been verified.
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