GHRP-6 Technical Specification Sheet
Molecular Properties
| Parameter |
Value |
| Chemical Name |
Growth Hormone Releasing Peptide-6 |
| Amino Acid Sequence |
His-D-Trp-Ala-Trp-D-Phe-Lys-NH₂ |
| Molecular Formula |
C₄₆H₅₆N₁₂O₆ |
| Molecular Weight |
872.44 g/mol |
| CAS Number |
87616-84-0 |
| Sequence Length |
6 amino acids (synthetic hexapeptide with D-amino acids) |
| Receptor Target |
Growth Hormone Secretagogue Receptor 1a (GHS-R1a) / Ghrelin receptor; CD36 (additional effects) |
Physical Properties
| Property |
Specification |
| Appearance |
White to off-white lyophilized powder |
| Solubility |
Soluble in water or bacteriostatic water at ≥1 mg/mL; pH 5.0-7.0 |
| pH (1% solution) |
5.0 - 7.0 |
| Hygroscopicity |
Low to moderate; standard desiccated storage |
| Solution Stability |
Stable at 4°C for 10-14 days; D-amino acids enhance stability |
Analytical Specifications
| Test |
Specification |
| HPLC Purity |
≥98.0% |
| Mass Spectrometry |
Confirmed [M+H]⁺ = 872.44 ± 0.5 Da |
| Peptide Content |
≥95% (by amino acid analysis) |
| Endotoxin Level |
<1.0 EU/mg |
| Acetate Content |
≤5% |
| TFA Content |
≤0.1% |
| Water Content |
≤6% (Karl Fischer) |
Storage Parameters
| Condition |
Specification |
| Lyophilized Storage |
-20°C, desiccated |
| Lyophilized Shelf Life |
24-36 months when stored properly |
| Reconstituted Storage |
2-8°C for up to 14 days; -20°C for up to 3 months |
| Reconstitution Protocol |
Add 1-2 mL sterile water or bacteriostatic water to 5 mg vial; gentle vortex 30 seconds |
| Freeze-Thaw Cycles |
Tolerates up to 5 cycles; D-amino acids provide stability |
| Light Sensitivity |
Low; standard laboratory storage acceptable |
Research Dosing Reference
| Application |
Typical Dose Range |
Frequency |
Route |
| In Vitro Pituitary Cell Assays |
10-1000 nM |
Acute stimulation (30 min to 2 hours) |
Culture media |
| Small Animal Models (Rodent) |
50-500 μg/kg |
1-3x daily |
SC or IV |
| GH Secretion Studies |
100-300 μg/kg |
Single dose or BID/TID for 7-28 days |
SC preferred |
| Appetite/Feeding Studies |
200-800 μg/kg |
30-60 min before feeding measurements |
SC or IP |
Note: Dosing information is for research reference only. GHRP-6 is intended for laboratory research. Notable for strongest appetite-stimulating effects among GHRPs.
Key Research Studies
| Year |
Study Focus |
Key Findings |
| 1984 |
Initial discovery and GH-releasing activity |
First synthetic hexapeptide GHRP identified by Bowers group; demonstrated potent GH release with EC₅₀ of 0.2-2 nM in vitro; 100-1000x more potent than GHRH on molar basis |
| 1996 |
Appetite stimulation and food intake |
GHRP-6 (300-600 μg/kg SC) increased food intake by 60-100% within 2 hours; effect mediated via hypothalamic NPY/AgRP neurons; strongest orexigenic effect among early GHRPs |
| 2002 |
CD36 receptor interaction |
Identified CD36 (fatty acid translocase) as secondary target for GHRP-6; mediated anti-inflammatory and cardioprotective effects independent of GHS-R1a; Ki ~100-500 nM at CD36 |
| 2008 |
Dual receptor mechanism characterization |
GHRP-6 effects dissected: GH release via GHS-R1a (blocked by [D-Lys3]-GHRP-6); appetite via GHS-R1a; wound healing and fibrosis effects via CD36; demonstrated unique dual-target pharmacology |
Mechanism of Action
| Biological Pathway |
Description |
| GHS-R1a Activation (Primary) |
Binds ghrelin receptor (GHS-R1a), Gq-coupled GPCR; high affinity (Kd ~0.5-5 nM); stimulates GH release and appetite |
| GH Secretion |
Activates pituitary somatotrophs → PLC/PKC → Ca²⁺ mobilization → GH release; peak GH at 20-40 minutes post-dose; pulsatile pattern |
| Appetite Stimulation |
Activates arcuate NPY/AgRP neurons; strongest hunger effect in GHRP family; increases ghrelin-like orexigenic signaling; food intake peaks 1-3 hours post-dose |
| CD36 Receptor Effects |
Binds CD36 (moderate affinity); anti-inflammatory actions; modulates fatty acid uptake; cardioprotective and wound healing properties |
| Half-Life |
20-30 minutes (IV/SC); D-amino acids provide peptidase resistance |
Comparative Analysis: GHRP-6 vs GHRP-2
| Parameter |
GHRP-6 |
GHRP-2 |
| Sequence Position 1 |
L-His |
D-Ala |
| Sequence Position 2 |
D-Trp |
D-2-Nal |
| GH Release Potency |
High (EC₅₀ ~0.2-2 nM) |
High (EC₅₀ ~0.1-1 nM) |
| Appetite Stimulation |
Very strong (+60-100%) |
Strong (+40-60%) |
| CD36 Interaction |
Yes (moderate affinity) |
Minimal |
| Clinical Development |
Research tool |
Advanced to human trials |
Quality Control Parameters
| Test Method |
Acceptance Criteria |
| Appearance (visual) |
White to off-white powder; no aggregation or discoloration |
| Chiral Purity |
D-amino acids at positions 2 and 5 confirmed; >98% correct stereochemistry |
| RP-HPLC (purity) |
Main peak ≥98.0%; no single impurity >0.5% |
| ESI-MS (identity) |
[M+H]⁺ = 872.44 ± 0.5 Da confirmed |
| Biological Activity |
≥85% potency vs reference in GH release assay |
Structure-Activity Relationship
| Position |
Amino Acid |
Structural Role |
| 1 |
L-His |
N-terminal; imidazole ring; pH-dependent charge; distinguishes from GHRP-2 |
| 2 |
D-Trp |
Critical for receptor binding; D-configuration essential for activity and stability |
| 3 |
L-Ala |
Conformational spacer; small side chain |
| 4 |
L-Trp |
Essential for GHS-R1a activation; indole ring interactions |
| 5 |
D-Phe |
Receptor selectivity; D-configuration prevents degradation |
| 6 |
L-Lys-NH₂ |
C-terminal; positive charge; amidation absolutely required |
Reported Biological Effects
| Effect Category |
Observed Changes |
Timeframe |
| GH Secretion |
Peak GH increase 5-15x baseline; occurs 20-40 min post-dose; duration 1-2 hours |
Acute (minutes to hours) |
| IGF-1 Elevation |
Increased 30-60% with repeated dosing; cumulative with chronic administration |
7-14 days |
| Appetite/Food Intake |
Increased food intake 60-100%; strongest effect in GHRP class; peak 1-3 hours |
Acute (1-4 hours) |
| Anti-inflammatory |
Reduced inflammatory markers; CD36-mediated effects; cardio/wound healing benefits |
24-72 hours |
Disclaimer: This product is intended for research use only. Not for human or veterinary diagnostic or therapeutic use. GHRP-6 exhibits the strongest appetite-stimulating effects in the GHRP family.