Compound monograph
GHRP-6
GHRP-6 is a synthetic hexapeptide with a C-terminal amide, characterized as an agonist at the growth hormone secretagogue receptor.
01
Identity & nomenclature
GHRP-6 is a synthetic hexapeptide with a C-terminal amide, characterized as an agonist at the growth hormone secretagogue receptor.
GHRP-6 is a hexapeptide with a C-terminal amide. A separate PubChem record for the same formula and mass carries a synonym belonging to GHRP-2, a different peptide; identity should be established against CAS 87616-84-0 rather than by name matching alone.
Declared aliases and development codes: Hexapeptide-2, Growth hormone-releasing peptide-6.
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Molecular properties
| Molecular formula | C46H56N12O6 |
|---|---|
| Molecular mass | 873 Da |
| CAS Registry Number | 87616-84-0 |
| PubChem CID | 9919153 |
| UNII | 4H7N4I6X6A |
| Three-letter sequence | His–D-Trp–Ala–Trp–D-Phe–Lys |
| Terminal groups | Free N-terminus; C-terminal amide |
Six residues, His-D-Trp-Ala-Trp-D-Phe-Lys, with a free N-terminus and a C-terminal amide, as encoded by PubChem CID 9919153. No one-letter string is recorded, because it cannot show the D-configuration of Trp2 and Phe5. Summing the six residues, removing five waters and converting the C-terminal carboxyl to an amide gives C46H56N12O6 and 873.03 Da, reproducing the recorded formula.
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Structural characteristics
The growth hormone secretagogue receptor was cloned and characterized as an orphan G-protein-coupled receptor mediating the activity of the growth hormone-releasing peptides. GHRP-6 activated a receptor family member isolated from a pufferfish genomic library on expression in HEK293 cells, and the source review reports that the receptor has been conserved for at least 400 million years, with ghrelin confirmed as its full endogenous agonist. Ipamorelin, also in this library, was identified within a series of compounds lacking the central Ala-Trp dipeptide of GHRP-1, and was reported not to raise ACTH and cortisol at doses where GHRP-6 and GHRP-2 did.
- D-tryptophan at position 2
- D-phenylalanine at position 5
Terminal features: Free N-terminus, C-terminal amide.
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Molecular targets & mechanisms
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Analytical considerations
The molecular formula contains no sulfur. PubChem CID 9919153 encodes D-tryptophan at position 2 and D-phenylalanine at position 5, with a free His1 amino group and a Lys6 amide; a plain one-letter sequence cannot specify those configurations. Because a second PubChem record shares this formula and mass while carrying a different peptide's synonym, mass alone does not establish identity within this compound family; sequence-level confirmation is required.
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 Pralmorelin (GHRP-2)
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
Primary rat pituitary cells
In primary rat pituitary cells, the study reported GHRP-6-associated growth hormone release with an assay-specific Emax of 100%.
Reference [2]Gq-coupled ghrelin receptor cryo-electron microscopy preparation
Using a Gq-coupled ghrelin receptor preparation, the study reported a cryo-electron microscopy structure with the synthetic agonist GHRP-6 bound to the receptor.
Reference [5]Gq-coupled ghrelin receptor cryo-electron microscopy complex
In a Gq-coupled ghrelin receptor cryo-electron microscopy complex, the study observed the GHRP-6 C-terminus inserting into the helix bundle and its N-terminus facing the extracellular vestibule.
Reference [5]
Animal studies
Swine
In swine, the study observed increased plasma ACTH and cortisol after GHRP-6 administration.
Reference [2]Swine
In swine, the study reported no change in plasma FSH, LH, PRL or TSH with the tested GH secretagogues, which included GHRP-6.
Reference [2]
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Verified bibliography
Cited studies by type
The 5 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
Growth hormone secretagogue receptor family members and ligands.Smith RG, Leonard R, Bailey AR, Palyha O, Feighner S, Tan C, Mckee KK, Pong SS, Griffin P, Howard A
Endocrine · 2001-02 · Review
currentReference 2
Ipamorelin, the first selective growth hormone secretagogue.Raun K, Hansen BS, Johansen NL, Thøgersen H, Madsen K, Ankersen M, Andersen PH
European journal of endocrinology · 1998-11 · Journal Article
currentReference 3
Structure of an antagonist-bound ghrelin receptor reveals possible ghrelin recognition mode.Shiimura Y, Horita S, Hamamoto A, Asada H, Hirata K, Tanaka M, Mori K, Uemura T, Kobayashi T, Iwata S, Kojima M
Nature communications · 2020-08-19 · Journal Article
currentReference 4
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 5
Molecular recognition of an acyl-peptide hormone and activation of ghrelin receptor.Wang Y, Guo S, Zhuang Y, Yun Y, Xu P, He X, Guo J, Yin W, Xu HE, Xie X, Jiang Y
Nature communications · 2021-08-20 · 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 |
|---|---|
| Smith RG et al. 2001 | Review article |
| Raun K et al. 1998 | Study models reported: in vitro; animal (rat, swine) · from the abstract |
| Shiimura Y et al. 2020 | Study models reported: in vitro · from the abstract |
| Thomas A et al. 2011 | Study models reported: in vitro · from the abstract |
| Wang Y et al. 2021 | Study models reported: in vitro · from the abstract |
Compare
Record history
Published 2026-09-04.
- : Sequence and structure, Analytical notes
- : References
- : 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. GHRP-6. Published 2026-09-04; updated 2026-10-14. https://purelypeptides.org/research/compounds/ghrp-6/
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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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