GHRP-6
Growth Hormone Releasing Peptide-6, Growth hormone-releasing hexapeptide, His-D-Trp-Ala-Trp-D-Phe-Lys-NH2
Hypothalamic targets for growth hormone secretagogues.
Robinson. I C IC
Key Findings
- GH secretagogues trigger GH release both directly at the pituitary and via hypothalamic neurons.
- An intact GHRH system is required for the full GH‑boosting effect of these peptides.
- The pattern of administration (e.g., intermittent vs. continuous) strongly influences the magnitude of GH release.
- GHS also activate the ACTH‑cortisol axis, indicating broader central hormonal effects.
Practical Outcomes
- For biohackers, timing matters – using short, intermittent doses (e.g., before sleep or after workouts) may give a stronger GH spike than a constant infusion. Pairing GHRP‑6 with a GHRH analog could enhance results. Watch for possible cortisol elevation, especially with high‑frequency dosing, and consider occasional monitoring of stress hormones.
Summary
The study shows that growth‑hormone secretagogues like GHRP‑6 don’t just pull GH out of the pituitary – they also work in the brain, need a working GHRH system, and can boost cortisol. How you give the peptide (timing and pattern) changes the GH response, and the drugs can affect other hormones too.
Abstract
Various novel growth hormone (GH) secretagogues have been developed. GH secretagogues release GH directly from the pituitary via a pathway distinct from that involving GH-releasing hormone (GHRH). However, they also act centrally to activate hypothalamic neurones, and require an intact GHRH system for potent in vivo activity. Both normal and transgenic growth-retarded (Tgr) rats release GH in response to GH secretagogues, and their responses are sensitive to the pattern of secretagogue administration. GH secretagogues are not completely specific for GH release, but also activate the adrenocorticotrophin-adrenal axis, implying that they have additional central actions. The recent cloning of an endogenous receptor for GH secretagogues now makes it possible to identify central targets for their action. An endogenous receptor implies the existence of an endogenous ligand, but its site of production, relationship to the xenobiotic pharmacological agents and its underlying physiological relevance remain unclear.
Study Information
pubmed
1997
1997-11-01T00:00:00.000Z
10.1111/j.1651-2227.1997.tb18382.x
8
42