Leu-enkephalin vs Met-enkephalin
Head-to-head comparison of Leu-enkephalin (Tyr-Gly-Gly-Phe-Leu) and Met-enkephalin (Tyr-Gly-Gly-Phe-Met) — benefits, dosing, side effects, research data, and where to buy.
Research Score
| Property | Leu-enkephalin | Met-enkephalin |
|---|---|---|
| Category | Pain Management | Pain Management |
| Full Name | Tyr-Gly-Gly-Phe-Leu | Tyr-Gly-Gly-Phe-Met |
| Molecular Weight | 555.63 Da | 573.67 Da |
| Half-Life | 1-5 minutes in plasma | 1-5 minutes in plasma |
| Amino Acids | 5 | 5 |
| Typical Dose | 0.1-5 ug per animal | 0.1-5 ug per animal |
| Route | Intrathecal / intracerebroventricular | Intrathecal / intracerebroventricular |
| Purity | ≥98% | ≥98% |
| Studies Count | 1000 | 1200 |
| Research Status | Pre-clinical | Pre-clinical |
Leu-enkephalin Benefits
- ✓delta-opioid activity
- ✓endogenous analgesic model
- ✓receptor-selective pharmacology
- ✓nociception pathway research
Met-enkephalin Benefits
- ✓endogenous opioid signaling
- ✓analgesic reference ligand
- ✓spinal antinociception
- ✓neurochemical pain-pathway probe
Leu-enkephalin Dosing
Intrathecal 0.1-5 ug per animal|Intracerebroventricular 0.1-2 ug per animal|In vitro 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
Leu-enkephalin Side Effects
- ⚠sedation
- ⚠constipation-like opioid effects
- ⚠very short plasma stability
Met-enkephalin Side Effects
- ⚠sedation at higher exposure
- ⚠constipation-like opioid effects
- ⚠rapid enzymatic degradation
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.
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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