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Nociceptin / Orphanin FQ
Overview
Nociceptin, also known as orphanin FQ, is a 17-amino acid peptide that acts as the endogenous ligand for the nociceptin/orphanin FQ peptide (NOP) receptor, a member of the opioid receptor family with distinct pharmacology. Despite structural similarity to dynorphin A, nociceptin does not bind classical opioid receptors.
Mechanism of Action
Its effects on pain are complex and context-dependent, producing analgesia at the spinal level but pronociceptive or hyperalgesic effects at supraspinal sites. The peptide also modulates stress, anxiety, and reward pathways.
Research Summary & Key Findings
Preclinical research has extensively characterized nociceptin's bidirectional effects on pain processing across different anatomical sites and pain models. Clinical development has focused on small-molecule NOP receptor agonists and mixed NOP/mu-opioid ligands rather than the native peptide. Phase 2 trials of cebranopadol, a dual NOP/mu agonist, have shown analgesic efficacy in chronic pain, though nociceptin itself remains a research tool.
Clinical Status
Nociceptin / Orphanin FQ is in the research phase with limited clinical data in humans. Current evidence is primarily derived from preclinical (animal or in vitro) studies.
Administration Routes
References
Primary literature
- PubMed: "Nociceptin / Orphanin FQ"
Peer-reviewed literature indexed by the National Library of Medicine.
- ClinicalTrials.gov: "Nociceptin / Orphanin FQ"
Registered interventional and observational studies, including status and phase.
- PubChem: "Nociceptin / Orphanin FQ"
Chemical structure, molecular properties, and bioactivity data.
Study-level citations for this compound are being verified against the primary sources before publication. The database queries above return the current indexed literature in the meantime.
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View detailsNo lawful pathway today
Nociceptin / Orphanin FQ is not FDA-approved and does not currently have a lawful prescription or compounding pathway in the United States, so there is nothing for us to sell you here and no consultation to book. That can change: eight peptides moved back to a lawful pathway in February 2026.
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List Your PracticeDisclaimer: This information is provided for educational and research purposes only. It is not intended as medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before starting any peptide therapy. The Peptide Association does not endorse or recommend any specific treatment protocol. See our editorial policy for how this content is produced and reviewed.