C-peptide vs Met-enkephalin

Head-to-head comparison of C-peptide (Connecting peptide (C-peptide)) and Met-enkephalin (Tyr-Gly-Gly-Phe-Met) — benefits, dosing, side effects, research data, and where to buy.

Research Score

PropertyC-peptideMet-enkephalin
CategoryPain ManagementPain Management
Full NameConnecting peptide (C-peptide)Tyr-Gly-Gly-Phe-Met
Molecular Weight3020.3 Da573.67 Da
Half-Life~20-30 min1-5 minutes in plasma
Amino Acids315
Typical Doseno approved analgesic dose|research-only0.1-5 ug per animal
RouteIV|subQIntrathecal / intracerebroventricular
Purity≥98%≥98%
Studies Count461200
Research StatusPre-clinicalPre-clinical

C-peptide Benefits

  • diabetic neuropathy research
  • nerve function support
  • possible analgesic effect

Met-enkephalin Benefits

  • endogenous opioid signaling
  • analgesic reference ligand
  • spinal antinociception
  • neurochemical pain-pathway probe

C-peptide Dosing

0.5-1.0 mg/day in research|route varies by protocol

Met-enkephalin Dosing

Intrathecal 0.1-5 ug per animal|Intracerebroventricular 0.1-2 ug per animal|In vitro 1-100 nM

C-peptide Side Effects

  • injection-site reactions
  • unknown long-term safety

Met-enkephalin Side Effects

  • sedation at higher exposure
  • constipation-like opioid effects
  • rapid enzymatic degradation

Research Overview

C-peptide

C-peptide is not an approved analgesic, but multiple studies have examined its effects on peripheral nerve blood flow and neuropathy outcomes. The strongest relevance is in diabetic neuropathic pain rather than migraine.

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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Common Stacking Partners

C-peptide stacks with:

C-peptideConnecting peptide

Met-enkephalin stacks with:

gabapentinketamine
neuropathic-paindiabetic-neuropathynerve-repairopioid-peptideenkephalinmu-opioidanalgesia