Hexarelin Technical Specification Sheet
Molecular Properties
| Parameter |
Value |
| Chemical Name |
Hexarelin / Examorelin |
| Amino Acid Sequence |
His-D-2-Methyl-Trp-Ala-Trp-D-Phe-Lys-NH₂ |
| Molecular Formula |
C₄₇H₅₈N₁₂O₆ |
| Molecular Weight |
887.04 g/mol |
| CAS Number |
140703-51-1 |
| Sequence Length |
6 amino acids (synthetic hexapeptide with D-amino acids and methylation) |
| Receptor Target |
Growth Hormone Secretagogue Receptor 1a (GHS-R1a) / Ghrelin receptor; CD36 |
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; enhanced stability from D-amino acids and methylation |
Analytical Specifications
| Test |
Specification |
| HPLC Purity |
≥98.0% |
| Mass Spectrometry |
Confirmed [M+H]⁺ = 887.04 ± 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, protected from light |
| 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; superior stability vs unmodified peptides |
| Light Sensitivity |
Moderate; store in amber vials recommended |
Research Dosing Reference
| Application |
Typical Dose Range |
Frequency |
Route |
| In Vitro Pituitary Cell Assays |
1-500 nM |
Acute stimulation (30 min to 2 hours) |
Culture media |
| Small Animal Models (Rodent) |
50-300 μg/kg |
1-2x daily |
SC, IV, or oral |
| GH Secretion Studies |
100-200 μg/kg |
Single dose or BID for 7-28 days |
SC preferred |
| Cardioprotection Research |
80-160 μg/kg |
Daily or BID for 1-4 weeks |
SC or IV |
Note: Dosing information is for research reference only. Hexarelin is intended for laboratory research. Most potent GHRP for GH release; notable cardioprotective effects.
Key Research Studies
| Year |
Study Focus |
Key Findings |
| 1995 |
Discovery and potency characterization |
2-methyl-D-Trp modification at position 2 increased GH-releasing potency 5-10x vs GHRP-6; demonstrated EC₅₀ of 0.05-0.5 nM (most potent synthetic GHRP); maintained stability and oral bioactivity |
| 2000 |
Cardioprotective effects in ischemia models |
Hexarelin (80 μg/kg BID) reduced myocardial infarct size by 40-50%; effects partly GHS-R1a-independent; identified CD36 receptor interaction mediating cardiac protection |
| 2006 |
Multi-organ protective effects |
Chronic hexarelin administration protected heart, kidney, liver from ischemia-reperfusion injury; anti-apoptotic effects via CD36 activation; reduced inflammatory cytokines 30-50%; GH-independent mechanisms identified |
| 2011 |
Cortisol and prolactin co-secretion |
Hexarelin stimulation increased cortisol 2-3x and prolactin 3-5x alongside GH release; greatest ACTH/cortisol stimulation among GHRPs; limits therapeutic application but valuable research tool |
Mechanism of Action
| Biological Pathway |
Description |
| GHS-R1a Activation |
Most potent GHS-R1a agonist (Kd ~0.1-1 nM); 5-10x more potent than GHRP-6 for GH release; stimulates pituitary somatotrophs and hypothalamic GHRH neurons |
| GH/ACTH/Prolactin Secretion |
Strongest GH release among GHRPs; significant ACTH/cortisol co-stimulation (2-3x baseline); prolactin elevation (3-5x); peak GH at 15-30 minutes post-dose |
| CD36 Receptor Activation |
Binds CD36 (fatty acid translocase) with moderate affinity; mediates cardioprotection, anti-inflammatory effects, and anti-apoptotic actions independent of GH |
| Cardioprotection |
Direct cardiac effects via CD36; reduces oxidative stress; inhibits apoptosis; improves post-ischemic recovery; preserves contractile function |
| Half-Life |
30-70 minutes (IV/SC); 2-methyl modification increases stability; oral bioavailability 5-10% (unusual for peptides) |
Comparative Analysis: Hexarelin Potency
| Compound |
GH Release EC₅₀ |
Relative Potency |
ACTH/Cortisol Effect |
| Hexarelin |
0.05-0.5 nM |
10x (reference) |
Strong (2-3x) |
| GHRP-2 |
0.1-1 nM |
5-8x |
Moderate (1.5-2x) |
| GHRP-6 |
0.2-2 nM |
5x |
Moderate (1.5-2x) |
| Ipamorelin |
1-10 nM |
1x |
Minimal (no increase) |
| GHRH |
0.5-2 nM |
1-2x |
None |
Quality Control Parameters
| Test Method |
Acceptance Criteria |
| Appearance (visual) |
White to off-white powder; no discoloration |
| 2-Methyl-D-Trp Verification |
Position 2 modification confirmed by MS/MS; methylation >98% |
| Chiral Purity |
D-amino acids at positions 2 and 5 confirmed; >98% stereochemical purity |
| RP-HPLC (purity) |
Main peak ≥98.0%; no single impurity >0.5% |
| ESI-MS (identity) |
[M+H]⁺ = 887.04 ± 0.5 Da confirmed |
| Biological Activity |
≥90% potency vs reference in GH release assay |
Structure-Activity Relationship
| Position |
Amino Acid |
Structural Role |
| 1 |
L-His |
N-terminal; imidazole ring; similar to GHRP-6 |
| 2 |
D-2-Methyl-Trp |
KEY MODIFICATION: 2-methyl group increases potency 5-10x; D-configuration essential; enhanced receptor binding |
| 3 |
L-Ala |
Conformational spacer |
| 4 |
L-Trp |
Essential for GHS-R1a activation; indole ring critical |
| 5 |
D-Phe |
Receptor selectivity; D-configuration prevents degradation |
| 6 |
L-Lys-NH₂ |
C-terminal; positive charge; amidation required |
Reported Biological Effects
| Effect Category |
Observed Changes |
Timeframe |
| GH Secretion |
Peak GH increase 10-30x baseline (highest in GHRP class); occurs 15-30 min post-dose |
Acute (15-60 minutes) |
| ACTH/Cortisol |
Increased ACTH 2-3x, cortisol 2-3x (strongest among GHRPs); limits chronic use |
Acute (30-90 minutes) |
| Prolactin |
Elevated 3-5x baseline; dose-dependent response |
Acute (30-120 minutes) |
| Cardioprotection |
Reduced infarct size 40-50%; improved ejection fraction; anti-apoptotic effects |
Hours to days |
| Appetite |
Moderate increase (+20-40%); less than GHRP-6 but present |
1-3 hours |
Disclaimer: This product is intended for research use only. Not for human or veterinary diagnostic or therapeutic use. Hexarelin is the most potent GHRP but also stimulates ACTH/cortisol significantly.