Nociceptin vs Leu-enkephalin

Head-to-head comparison of Nociceptin (Nociceptin/orphanin FQ) and Leu-enkephalin (Tyr-Gly-Gly-Phe-Leu) — benefits, dosing, side effects, research data, and where to buy.

Research Score

PropertyNociceptinLeu-enkephalin
CategoryPain ManagementPain Management
Full NameNociceptin/orphanin FQTyr-Gly-Gly-Phe-Leu
Molecular Weight1881.1 Da555.63 Da
Half-Life~minutes1-5 minutes in plasma
Amino Acids175
Typical Doseno approved human dose|research-only0.1-5 ug per animal
Routeintrathecal|intranasalIntrathecal / intracerebroventricular
Purity≥98%≥98%
Studies Count441000
Research StatusPre-clinicalPre-clinical

Nociceptin Benefits

  • allodynia reduction
  • central pain modulation
  • neuropathic pain research

Leu-enkephalin Benefits

  • delta-opioid activity
  • endogenous analgesic model
  • receptor-selective pharmacology
  • nociception pathway research

Nociceptin Dosing

no established human dose|research-only dosing varies

Leu-enkephalin Dosing

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

Nociceptin Side Effects

  • sedation
  • dysphoria

Leu-enkephalin Side Effects

  • sedation
  • constipation-like opioid effects
  • very short plasma stability

Research Overview

Nociceptin

Nociceptin is a major pain-pathway peptide in the spinal cord, brainstem, and trigeminal system. Its relevance to migraine and neuropathic pain is mainly preclinical, where receptor-selective tools are being explored.

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.

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Common Stacking Partners

Nociceptin stacks with:

Orphanin FQOFQ

Leu-enkephalin stacks with:

gabapentinketamine
neuropathic-paintrigeminal-painopioid-likeopioid-peptideenkephalindelta-opioidanalgesia