Side-by-Side Comparison · 2026

Opiorphin vs Spinorphin

Opiorphin vs Spinorphin — mechanism, half-life, dosing, and research status compared. Which is right for your protocol?

Opiorphin
Opioid-Modulating Peptide

Opiorphin is a five-amino acid peptide (QRFSR) discovered in human saliva by Catherine Rougeot at the Pasteur Institute in 2006. It is an endogenous inhibitor of neutral endopeptidase (NEP/neprilysin) and aminopeptidase N (APN), two enzymes that rapidly degrade enkephalins in the...

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Spinorphin
Opioid-Modulating Peptide

Spinorphin is a 10-amino acid peptide (LVVYPWTQRF) isolated from bovine spinal cord by Nishizawa et al. 11 (neprilysin, NEP), functioning as an indirect opioid amplifier similar to opiorphin....

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Key Parameters
Parameter Opiorphin Spinorphin
Category Opioid-Modulating Peptide Opioid-Modulating Peptide
Research Preclinical Preclinical
Half-Life < 5 min (plasma) < 10 min (plasma)
Typical Dose Research only (mg/kg range) Research only (mg/kg range)
Frequency N/A N/A
Route IV, SC (research) IV, ICV (research)
FDA Status No approval No approval

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Frequently Asked Questions
What is the difference between Opiorphin and Spinorphin?
Opiorphin: Opiorphin is a five-amino acid peptide (QRFSR) discovered in human saliva by Catherine Rougeot at the Pasteur Institute in 2006. It is an endogenous inhibitor of neutral endopeptidase (NEP/neprilysin)... Spinorphin: Spinorphin is a 10-amino acid peptide (LVVYPWTQRF) isolated from bovine spinal cord by Nishizawa et al. 11 (neprilysin, NEP), functioning as an indirect opioid amplifier similar to opiorphin....
Which has a longer half-life, Opiorphin or Spinorphin?
Opiorphin half-life: < 5 min (plasma). Spinorphin half-life: < 10 min (plasma).
Can you stack Opiorphin and Spinorphin?
Opiorphin and Spinorphin are in the same category and used together in research protocols. Always consult relevant literature and follow appropriate guidelines.

For research use only. Not medical advice. ASCEND does not conduct or endorse any specific research protocol. Always consult relevant scientific literature and regulatory guidelines.