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Growth hormone secretagogue

GHRP-6

Growth Hormone Releasing Peptide-6Growth Hormone-Releasing HexapeptideGHRP6SKF-110679His-D-Trp-Ala-Trp-D-Phe-Lys-NH2GHRP-6 acetate

GHRP-6 is a synthetic hexapeptide growth hormone secretagogue and ghrelin-receptor (GHS-R1a) agonist studied in research settings, with no approved medical use.

Overview

GHRP-6 (Growth Hormone Releasing Peptide-6) is a synthetic hexapeptide with the sequence His-D-Trp-Ala-Trp-D-Phe-Lys-NH2. It is the founding member of the growth hormone-releasing peptide (GHRP) family, developed from structure-activity work by Cyril Y. Bowers and colleagues and characterized in the mid-1980s as one of the first peptides shown to release growth hormone through a mechanism distinct from growth hormone-releasing hormone (GHRH).

Mechanistically, GHRP-6 acts as an agonist at the growth hormone secretagogue receptor type 1a (GHS-R1a), which was later identified as the endogenous receptor for the hormone ghrelin. Receptor activation in the pituitary and hypothalamus is coupled to Gq/11 / phospholipase C signaling and intracellular calcium release, and in research models is associated with pulsatile growth hormone secretion. GHRP-6 is also noted for the most pronounced appetite stimulation of the GHRP family. A separate, growth-hormone-independent pathway through the scavenger receptor CD36 has been reported in preclinical studies to underlie cytoprotective, anti-inflammatory, and cardioprotective effects in tissue and animal models.

GHRP-6 has no approved therapeutic indication. It is not authorized as a medicine by the FDA, EMA, MHRA, or other major regulators, carries no ATC classification, and is prohibited at all times in sport by the World Anti-Doping Agency. It is supplied only as a research chemical (commonly as the acetate salt) and is not intended for human or veterinary use. Reported effects on cortisol, ACTH, and prolactin, together with the absence of standardized purity and sterility controls from non-pharmaceutical suppliers, are relevant considerations in any research handling.

Mechanism, evidence & status

GHRP-6 is a synthetic hexapeptide growth hormone secretagogue that acts as an agonist at the growth hormone secretagogue receptor type 1a (GHS-R1a), the same receptor later identified as the endogenous ghrelin receptor. Receptor activation in the pituitary and hypothalamus triggers Gq/11-coupled phospholipase C signaling and intracellular calcium release, which in research models is associated with pulsatile growth hormone release and pronounced appetite stimulation. A separate, GH-independent pathway through the scavenger receptor CD36 has been reported to mediate cytoprotective and anti-inflammatory effects in preclinical tissue studies.

Human evidence
Preclinical and early clinical research; no approved therapeutic indication
Regulatory status
Not approved as a medicine by the FDA, EMA, MHRA, or any other major regulator; has no ATC classification. Prohibited at all times in sport by WADA (Prohibited List class S2, peptide hormones and mimetics). Sold only as a research chemical, not for human or veterinary use.
Research applications
  • Used in endocrinology research as a pharmacological probe of the ghrelin/GHS-R1a axis and pituitary growth hormone release.
  • Investigated in preclinical models for appetite and feeding regulation in cachexia/wasting contexts.
  • Studied in animal models for GH-independent cytoprotective, anti-inflammatory, and cardioprotective effects attributed to CD36 signaling.
  • Employed as a reference comparator in the development and characterization of other growth hormone secretagogues.
Safety considerations
  • Not an approved drug; no established human safety profile, standardized purity, or quality controls outside regulated pharmaceutical manufacturing (PubChem CID 4345065).
  • GHS-R1a agonism has been reported to raise circulating ACTH, cortisol, and prolactin alongside growth hormone in a dose-dependent manner, and GHRP-6 causes the strongest appetite stimulation of the GHRP family, which may be undesirable in some research contexts.
  • As an injectable research peptide, contamination, dosing, and sterility risks are unmanaged; product identity and concentration from non-pharmaceutical suppliers are frequently unverified.
  • Banned in competitive sport by WADA; possession/use carries anti-doping and legal-supply implications in many jurisdictions.
References
  1. [1]PubChem Compound: GHRP-6 (CID 4345065)PubChem (NIH)
  2. [2]GHRP-6 — Wikipedia (chemistry, CAS, regulatory status)Wikipedia
  3. [3]Berlanga-Acosta et al. (2016): GHRP-6 and related secretagogue synthetic peptides — a mine of medical potentialitiesIntegrative Molecular Medicine (review)
  4. [4]GHRP-6 — ChemicalBook (CAS 87616-84-0 properties)ChemicalBook