Identity
What is GHRP-6?
- Type
- Synthetic hexapeptide (GHRP family)
- Sequence
- His-D-Trp-Ala-Trp-D-Phe-Lys
- Amino acids
- 6
- Primary target
- Growth-hormone-secretagogue receptor (GHS-R1a)
- Research family
- GH secretagogue
- Use classification
- Research Use Only
Science Library · GH releasing peptide
GHRP-6 the science.
GHRP-6 (growth hormone-releasing peptide 6) is one of the original synthetic hexapeptides developed to study growth-hormone release. It acts on the growth-hormone-secretagogue (ghrelin) receptor and was among the molecules that led researchers to discover ghrelin itself. Research includes preclinical work and early-phase human studies. The summary below reflects published research.
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6 aa
Peptide length
GHS-R1a
Primary target
Human studies
Evidence stage
Investigational
Regulatory status
How it works
Mechanism at a glance
Compound
GHRP-6
Action
Agonizes the ghrelin receptor
Effect
Stimulates GH release
Studied in
Healthy-volunteer studies
Evidence to date
In vitro
Animal
Human
Evidence to date: preclinical plus early-phase human studies. Not FDA-approved.
What it is
GHRP-6 is a synthetic six-amino-acid peptide (His-D-Trp-Ala-Trp-D-Phe-Lys) and a foundational member of the growth-hormone-releasing-peptide family. It does not act on the GHRH receptor; instead it binds the growth-hormone-secretagogue receptor (GHS-R1a). Its study was historically important — the search for the natural ligand of the receptor GHRP-6 activated ultimately led to the identification of ghrelin.
In research, GHRP-6 serves as a classic tool compound for dissecting the GHS-receptor pathway and its interaction with GHRH signaling. It is an investigational compound, not an approved medicine.
The pathway under study: the ghrelin (GHS) receptor
GHRP-6 research is organized around the ghrelin-receptor route to GH release:
- GHS-R1a activation — binding the ghrelin receptor on pituitary somatotrophs is studied for how it evokes GH secretion.
- GHRH interaction — investigators examine the amplified GH response when GHRP-6 is combined with GHRH, a hallmark of GHS-receptor research.
- Receptor pharmacology — GHRP-6 is widely used to characterize GHS-receptor binding and downstream signaling in cell and tissue models.
What research has explored
GHRP-6 has an extensive preclinical literature plus early-phase human research:
- GH-receptor blockade study (2001). A study in the Journal of Clinical Endocrinology & Metabolism examined GHRP-6-mediated GH release in humans under GH-receptor blockade, probing the feedback architecture of the axis.
- Diagnostic combination testing (2005). Research in the European Journal of Endocrinology evaluated a GHRH/GHRP-6 combination as a provocative test for GH deficiency.
These human studies are early-phase and investigational. GHRP-6 is not FDA-approved, and this material is supplied for research use only.
Current state of the evidence
GHRP-6 is an investigational ghrelin-receptor agonist with a long history as a research tool. Published evidence includes early-phase human studies alongside extensive preclinical work, but it is not FDA-approved and no approved indication, dosing, or therapeutic claim applies. GHRP-6 is supplied strictly as a research material for laboratory investigation.
Compound Snapshot
At a glance
Evidence base
Research maturity
Investigational
Human study data
Not FDA-approved
Maturity
Clinical (early phase)
Extensive preclinical work plus published early-phase human studies; still investigational.
Status
Not FDA-approved
No approved indication, dosing, or therapeutic claim. Supplied for research use only.
Sources & References
Peer-reviewed research and database records
J. Clinical Endocrinology & Metabolism / PubMed
Blockade of the growth hormone (GH) receptor unmasks rapid GH-releasing peptide-6-mediated tissue-specific insulin resistance
2001 · PMID 11158013 · DOI 10.1210/jcem.86.2.7173 View SourceEuropean Journal of Endocrinology / PubMed
The GHRH/GHRP-6 test for the diagnosis of GH deficiency in elderly or severely obese patients
2005 · PMID 15817913 · DOI 10.1530/eje.1.01887 View SourcePubChem
GHRP-6 compound search
NIH PubChem lookup for molecular identity and structure records. View SourcePubMed
GHRP-6 literature search
NCBI PubMed index for primary papers, reviews, and PMID-linked records. View SourceFor research use only. Not for human or veterinary use. These products have not been evaluated by the FDA. Nothing on this page is medical advice or a therapeutic claim.
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