GHRP-2 Technical Specification Sheet
Molecular Properties
| Parameter |
Value |
| Chemical Name |
Growth Hormone Releasing Peptide-2 / Pralmorelin |
| Amino Acid Sequence |
D-Ala-D-2-Nal-Ala-Trp-D-Phe-Lys-NH₂ |
| Molecular Formula |
C₄₅H₅₅N₉O₆ |
| Molecular Weight |
817.97 g/mol |
| CAS Number |
158861-67-7 |
| Sequence Length |
6 amino acids (synthetic hexapeptide with D-amino acids) |
| Receptor Target |
Growth Hormone Secretagogue Receptor 1a (GHS-R1a) / Ghrelin receptor |
Physical Properties
| Property |
Specification |
| Appearance |
White to off-white lyophilized powder |
| Solubility |
Soluble in water or bacteriostatic water at ≥1 mg/mL; pH 5.5-7.5 |
| pH (1% solution) |
5.5 - 7.5 |
| 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]⁺ = 817.97 ± 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/Ghrelin Research |
200-600 μg/kg |
30-60 min before measurements |
SC or IP |
Note: Dosing information is for research reference only. GHRP-2 is intended for laboratory research. Mimics ghrelin action at GHS-R1a receptor; stimulates appetite and GH release.
Key Research Studies
| Year |
Study Focus |
Key Findings |
| 1995 |
Discovery and characterization of GHS-R |
GHRP-2 identified as potent synthetic ligand for orphan GPCR (later named GHS-R1a); demonstrated EC₅₀ of 0.1-1 nM for GH release; 10-100x more potent than GHRH in vitro |
| 1999 |
Synergy with GHRH |
Combined GHRP-2 + GHRH administration produced synergistic GH response (5-10x vs either alone); demonstrated distinct receptor mechanisms and complementary signaling pathways |
| 2006 |
Appetite stimulation and orexigenic effects |
GHRP-2 (300 μg/kg SC) increased food intake by 40-60% within 2 hours; activated NPY/AgRP neurons in arcuate nucleus; effects blocked by GHS-R1a antagonists |
| 2012 |
Cardioprotective and anti-inflammatory effects |
GHRP-2 treatment (200 μg/kg twice daily) reduced infarct size by 30-40% in cardiac ischemia models; decreased inflammatory markers (IL-6, TNF-α); GHS-R1a-dependent and independent mechanisms identified |
Mechanism of Action
| Biological Pathway |
Description |
| GHS-R1a Activation |
Binds ghrelin receptor (GHS-R1a), Gq-coupled GPCR; high affinity (Kd ~0.5-5 nM); expressed in pituitary, hypothalamus, heart, adipose |
| GH Secretion |
Activates pituitary somatotrophs → PLC/PKC pathway → Ca²⁺ mobilization → GH release; peak GH at 15-30 minutes post-dose |
| Hypothalamic Effects |
Stimulates arcuate NPY/AgRP neurons → appetite increase; modulates GHRH neuron activity; amplifies endogenous GH pulses |
| Peripheral Actions |
Cardioprotection via GHS-R1a-dependent and independent mechanisms; anti-inflammatory effects; modulation of adipocyte function |
| Half-Life |
20-30 minutes (IV/SC); D-amino acids provide resistance to peptidases vs natural peptides |
Comparative Analysis: GHRP Family
| Compound |
MW (Da) |
GH Potency |
Appetite Effect |
Cortisol/Prolactin |
| GHRP-2 |
817.97 |
High (EC₅₀ ~0.1-1 nM) |
Strong (+40-60%) |
Moderate increase |
| GHRP-6 |
872.44 |
High (EC₅₀ ~0.2-2 nM) |
Very strong (+60-100%) |
Moderate increase |
| Hexarelin |
887.04 |
Very high (EC₅₀ ~0.05-0.5 nM) |
Moderate (+20-40%) |
Strong increase |
| Ipamorelin |
711.85 |
Moderate (EC₅₀ ~1-10 nM) |
Minimal |
No increase (selective) |
Quality Control Parameters
| Test Method |
Acceptance Criteria |
| Appearance (visual) |
White to off-white powder; no aggregation |
| Chiral Purity |
D-amino acids at positions 1, 2, 5 confirmed; >98% correct stereochemistry |
| RP-HPLC (purity) |
Main peak ≥98.0%; no single impurity >0.5% |
| ESI-MS (identity) |
[M+H]⁺ = 817.97 ± 0.5 Da confirmed |
| Biological Activity |
≥85% potency vs reference in GH release assay |
Structure-Activity Relationship
| Position |
Amino Acid |
Structural Role |
| 1 |
D-Ala |
N-terminal stability; prevents aminopeptidase degradation |
| 2 |
D-2-Nal (D-2-naphthylalanine) |
Critical for receptor binding; aromatic interaction with GHS-R1a |
| 3 |
L-Ala |
Conformational spacer |
| 4 |
L-Trp |
Essential for activity; indole ring interactions |
| 5 |
D-Phe |
Receptor selectivity; D-configuration critical |
| 6 |
L-Lys-NH₂ |
C-terminal; positive charge; amidation essential |
Reported Biological Effects
| Effect Category |
Observed Changes |
Timeframe |
| GH Secretion |
Peak GH increase 5-20x baseline; occurs 15-30 min post-dose; duration 1-2 hours |
Acute (minutes to hours) |
| IGF-1 Levels |
Increased 30-50% with repeated dosing; cumulative effect over 1-2 weeks |
7-14 days |
| Appetite |
Increased food intake 40-60%; peak effect 1-3 hours post-dose |
Acute (1-4 hours) |
| Body Composition |
Increased lean mass 2-5%; modest fat reduction with chronic dosing |
4-8 weeks |
Disclaimer: This product is intended for research use only. Not for human or veterinary diagnostic or therapeutic use. GHRP-2 is a potent GHS-R1a agonist with both GH-releasing and orexigenic properties.