Endomorphin-1 vs Met-enkephalin
Head-to-head comparison of Endomorphin-1 (Tyr-Pro-Trp-Phe-NH2) and Met-enkephalin (Tyr-Gly-Gly-Phe-Met) — benefits, dosing, side effects, research data, and where to buy.
Research Score
| Property | Endomorphin-1 | Met-enkephalin |
|---|---|---|
| Category | Pain Management | Pain Management |
| Full Name | Tyr-Pro-Trp-Phe-NH2 | Tyr-Gly-Gly-Phe-Met |
| Molecular Weight | 610.71 Da | 573.67 Da |
| Half-Life | Minutes in plasma | 1-5 minutes in plasma |
| Amino Acids | 4 | 5 |
| Typical Dose | 0.1-10 ug per animal | 0.1-5 ug per animal |
| Route | Intrathecal / subcutaneous | Intrathecal / intracerebroventricular |
| Purity | ≥98% | ≥98% |
| Studies Count | 600 | 1200 |
| Research Status | Pre-clinical | Pre-clinical |
Endomorphin-1 Benefits
- ✓mu-opioid selectivity
- ✓potent antinociception
- ✓endogenous peptide scaffold
- ✓useful for receptor-discovery studies
Met-enkephalin Benefits
- ✓endogenous opioid signaling
- ✓analgesic reference ligand
- ✓spinal antinociception
- ✓neurochemical pain-pathway probe
Endomorphin-1 Dosing
Intrathecal 0.1-10 ug per animal|Subcutaneous 0.1-5 ug per animal|In vitro 0.1-100 nM
Met-enkephalin Dosing
Intrathecal 0.1-5 ug per animal|Intracerebroventricular 0.1-2 ug per animal|In vitro 1-100 nM
Endomorphin-1 Side Effects
- ⚠respiratory depression at high exposure
- ⚠sedation
- ⚠tolerance and dependence potential
Met-enkephalin Side Effects
- ⚠sedation at higher exposure
- ⚠constipation-like opioid effects
- ⚠rapid enzymatic degradation
Research Overview
Endomorphin-1
Endomorphin-1 is a key research peptide in studies of endogenous mu-opioid signaling and spinal analgesia. Like other peptide analgesics, its main translational hurdles are enzymatic instability, limited oral bioavailability, and delivery across barriers.
Met-enkephalin
Met-enkephalin has been extensively used in receptor pharmacology and nociception studies to map mu and delta opioid biology. The main limitation in translational work is very short half-life from peptidase cleavage and poor systemic stability.
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