GHRP-6¶
GHRP-6 (Growth Hormone Releasing Peptide-6, CAS 87616-84-0) is a first-generation synthetic hexapeptide ghrelin receptor (GHS-R1a) agonist with a molecular weight of approximately 873.0 Da and formula C₄₆H₅₆N₁₂O₆. As the prototypical growth hormone-releasing peptide from which subsequent analogs were developed, GHRP-6 is a powerful research tool for studying ghrelin receptor pharmacology, GH secretion, and appetite regulation through hypothalamic circuits.
Technical Specifications¶
| Property | Value |
|---|---|
| CAS Number | 87616-84-0 |
| Molecular Formula | C₄₆H₅₆N₁₂O₆ |
| Molecular Weight | ~873.0 Da |
| Purity | ≥99% (HPLC-verified) |
| Appearance | Lyophilized white powder |
| Solubility | Soluble in sterile water and aqueous buffers |
| Storage | -20°C (lyophilized), 2–8°C (reconstituted) |
Mechanism of Action¶
GHRP-6 is a full agonist at GHS-R1a (the ghrelin receptor), activating Gαq/11-mediated phospholipase C (PLC) signaling in hypothalamic arcuate nucleus neurons and pituitary somatotrophs. PLC activation generates IP₃ and DAG, leading to intracellular calcium mobilization and PKC activation, which together trigger GH secretory vesicle exocytosis. Simultaneously, GHRP-6 reduces the inhibitory tone of somatostatin on somatotroph function. A distinguishing feature of GHRP-6 is its pronounced effect on hypothalamic feeding circuits: GHS-R1a activation on NPY/AgRP neurons in the arcuate nucleus stimulates orexigenic signaling, potently increasing food intake through downstream melanocortin-4 receptor (MC4R) pathway inhibition. This appetite effect is notably stronger for GHRP-6 compared to GHRP-2 or ipamorelin due to subtle differences in receptor activation kinetics. When combined with GHRH analogs, GHRP-6 produces synergistic GH release through parallel Gαq and Gαs pathway activation.
Research Applications¶
- Primary: Appetite regulation and feeding behavior — hypothalamic NPY/AgRP signaling, ghrelin receptor orexigenic effects
- Secondary: GH axis pharmacology, ghrelin receptor structure-activity relationships, cachexia and wasting condition models
- Model Systems: In vitro (GHS-R1a-expressing cell lines), in vivo (food intake studies, GH release profiling, gastrectomy models examining ghrelin physiology)
Quality Control & Analytical Methods¶
- HPLC: ≥99% purity verification at 214/220 nm (C18 reversed-phase column)
- Mass Spectrometry: ESI-MS for molecular weight confirmation (~873.0 ±1.0 Da)
- Peptide Content: Amino acid analysis (AAA) for net peptide content determination
- Endotoxin: <1 EU/mg (LAL assay)
- TFA Content: <1% (ion chromatography)
Stability & Storage¶
| Condition | Stability |
|---|---|
| -20°C (lyophilized) | 24 months |
| 4°C (lyophilized) | 6 months |
| 25°C (lyophilized) | 1 month |
| Reconstituted (4°C) | 7 days |
| Reconstituted (-20°C) | 30 days |
Key Research References¶
- Bowers et al. (1984) — On the in vitro and in vivo activity of a new synthetic hexapeptide that acts on the pituitary to specifically release growth hormone. Endocrinology. PMID: 6090118
- Howard et al. (1996) — A receptor in pituitary and hypothalamus that functions in growth hormone release. Science. PMID: 8688086
- Wren et al. (2000) — Ghrelin enhances appetite and increases food intake in humans. J Clin Endocrinol Metab. PMID: 11134184
Source & Purchase¶
For researchers requiring research-grade GHRP 6 with full analytical documentation including HPLC, LC-MS, and Certificate of Analysis, visit the HK Peptides product page for specifications, bulk pricing, and ordering.
Related Molecules¶
- GHRP-2 — Ghrelin receptor agonist, lower appetite effect
- CJC-1295 (no DAC) — GHRH analog
- MK-677 — Oral GH secretagogue
- All Product Specifications
FAQ¶
Q: What purity level is standard for GHRP-6? A: HK Peptides supplies GHRP-6 at ≥99% purity by HPLC with full COA documentation.
Q: How should GHRP-6 be stored for research use? A: Lyophilized GHRP-6 should be stored at -20°C. Reconstituted solutions at 4°C for short-term use (up to 7 days).