Met-enkephalin vs Cosyntropin
Head-to-head comparison of Met-enkephalin (Tyr-Gly-Gly-Phe-Met) and Cosyntropin (Cosyntropin (ACTH 1-24)) — benefits, dosing, side effects, research data, and where to buy.
Research Score
| Property | Met-enkephalin | Cosyntropin |
|---|---|---|
| Category | Pain Management | Pain Management |
| Full Name | Tyr-Gly-Gly-Phe-Met | Cosyntropin (ACTH 1-24) |
| Molecular Weight | 573.67 Da | 2933.3 Da |
| Half-Life | 1-5 minutes in plasma | ~10 min |
| Amino Acids | 5 | 24 |
| Typical Dose | 0.1-5 ug per animal | 0.25 mg IV/IM diagnostic dose|off-label headache protocols vary |
| Route | Intrathecal / intracerebroventricular | IV|IM |
| Purity | ≥98% | ≥98% |
| Studies Count | 1200 | 61 |
| Research Status | Pre-clinical | Clinical research |
Met-enkephalin Benefits
- ✓endogenous opioid signaling
- ✓analgesic reference ligand
- ✓spinal antinociception
- ✓neurochemical pain-pathway probe
Cosyntropin Benefits
- ✓refractory migraine
- ✓anti-inflammatory signaling
- ✓headache rescue research
Met-enkephalin Dosing
Intrathecal 0.1-5 ug per animal|Intracerebroventricular 0.1-2 ug per animal|In vitro 1-100 nM
Cosyntropin Dosing
0.25 mg IV/IM|1 mg IV/IM
Met-enkephalin Side Effects
- ⚠sedation at higher exposure
- ⚠constipation-like opioid effects
- ⚠rapid enzymatic degradation
Cosyntropin Side Effects
- ⚠flushing
- ⚠nausea
Research Overview
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.
Cosyntropin
Cosyntropin is not a standard pain drug, but it appears in headache literature because ACTH analogs can help some patients with difficult migraine attacks. The analgesic rationale is partly tied to steroidogenic and anti-inflammatory effects.
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