Leu-enkephalin vs Endomorphin-1
Head-to-head comparison of Leu-enkephalin (Tyr-Gly-Gly-Phe-Leu) and Endomorphin-1 (Tyr-Pro-Trp-Phe-NH2) — benefits, dosing, side effects, research data, and where to buy.
Research Score
| Property | Leu-enkephalin | Endomorphin-1 |
|---|---|---|
| Category | Pain Management | Pain Management |
| Full Name | Tyr-Gly-Gly-Phe-Leu | Tyr-Pro-Trp-Phe-NH2 |
| Molecular Weight | 555.63 Da | 610.71 Da |
| Half-Life | 1-5 minutes in plasma | Minutes in plasma |
| Amino Acids | 5 | 4 |
| Typical Dose | 0.1-5 ug per animal | 0.1-10 ug per animal |
| Route | Intrathecal / intracerebroventricular | Intrathecal / subcutaneous |
| Purity | ≥98% | ≥98% |
| Studies Count | 1000 | 600 |
| Research Status | Pre-clinical | Pre-clinical |
Leu-enkephalin Benefits
- ✓delta-opioid activity
- ✓endogenous analgesic model
- ✓receptor-selective pharmacology
- ✓nociception pathway research
Endomorphin-1 Benefits
- ✓mu-opioid selectivity
- ✓potent antinociception
- ✓endogenous peptide scaffold
- ✓useful for receptor-discovery studies
Leu-enkephalin Dosing
Intrathecal 0.1-5 ug per animal|Intracerebroventricular 0.1-2 ug per animal|In vitro 1-100 nM
Endomorphin-1 Dosing
Intrathecal 0.1-10 ug per animal|Subcutaneous 0.1-5 ug per animal|In vitro 0.1-100 nM
Leu-enkephalin Side Effects
- ⚠sedation
- ⚠constipation-like opioid effects
- ⚠very short plasma stability
Endomorphin-1 Side Effects
- ⚠respiratory depression at high exposure
- ⚠sedation
- ⚠tolerance and dependence potential
Research Overview
Leu-enkephalin
Leu-enkephalin is a standard tool in opioid receptor and pain-transmission research because it helps distinguish delta- from mu-preferring signaling. Its research value is high, but its clinical utility is limited by rapid enzymatic breakdown and delivery challenges.
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.
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