Pain · Investigational
Nociceptin / Orphanin FQ
No lawful US pathway
01 · Overview
Nociceptin, also known as orphanin FQ (N/OFQ), is a 17-amino acid peptide identified in 1995 as the endogenous ligand of the opioid receptor-like ORL1 receptor, now called the NOP receptor (PMID 7566152). Its sequence resembles dynorphin A, but it does not activate classical opioid receptors (PMID 7481766).
Its effects on pain are complex: given into the brain of mice it caused hyperalgesia (PMID 7566152), and rodent studies show that spinal and supraspinal effects are bidirectional depending on dose and test, whereas NOP agonists produce only antinociception in nonhuman primates (PMID 26920014). The peptide also modulates stress, anxiety, and reward pathways.
02 · Research summary & key findings
In a small randomized placebo-controlled trial in patients with neurogenic detrusor overactivity, 10 days of intravesical N/OFQ increased bladder capacity and reduced incontinence episodes (PMID 17070267). Clinical development for pain has focused on small-molecule NOP agonists and mixed NOP/mu-opioid agonists rather than the native peptide. In a phase 2 trial in chronic low back pain, cebranopadol, a dual NOP/opioid receptor agonist, gave significant pain relief versus placebo, with discontinuations from adverse events at higher doses (PMID 28644196).
03 · Regulatory status
Nociceptin / Orphanin FQ is in the investigational stage. While preclinical and early-phase data exist, it has not received regulatory approval for clinical use in the United States.
No 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 we do not sell it and will not book a consultation for it. That can change: in 2026 FDA began reviewing several peptides for compounding. If you are working on the goal it is studied for, a licensed clinician can tell you what is lawfully available, which may be something else.
See the 2 FDA-approved compounds in Pain
Tell me if the status changes
One email, only if this compound's regulatory standing actually moves. Not a newsletter, not a sales sequence.
Looking for a lawful, clinician-prescribed option for injury recovery and tissue repair?
Nociceptin / Orphanin FQ is an investigational compound, is not FDA-approved, and has no lawful US compounding pathway, so we do not offer it and no clinician we work with will prescribe it. Products sold online as “research chemicals” are not made or tested to the standards required of medicines. If you are working on injury recovery and tissue repair, a licensed clinician can tell you at a free consultation whether an FDA-approved or lawfully compounded treatment fits you, or whether nothing does.
Explore lawful options (free intake)About 3 minutes. If a protocol is prescribed through our provider, we earn 10% of the sale. See the receipts.
04 · Administration routes
- Endogenous peptide
References
- [1]Daily intravesical instillation of 1 mg nociceptin/orphanin FQ for the control of neurogenic detrusor overactivity: a multicenter, placebo controlled, randomized exploratory study J Urol, 2006. PMID 17070267
- [2]Central N/OFQ-NOP Receptor System in Pain Modulation Adv Pharmacol, 2016. PMID 26920014
- [3]Cebranopadol, a novel first-in-class analgesic drug candidate: first experience in patients with chronic low back pain in a randomized clinical trial Pain, 2017. PMID 28644196
- [4]Orphanin FQ: a neuropeptide that activates an opioidlike G protein-coupled receptor Science, 1995. PMID 7481766
- [5]Isolation and structure of the endogenous agonist of opioid receptor-like ORL1 receptor Nature, 1995. PMID 7566152
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.
Related peptides in Pain
Disclaimer: 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. Clinicians: join the network.