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Endomorphin-2
Overview
Endomorphin-2 is a tetrapeptide (Tyr-Pro-Phe-Phe) that, like endomorphin-1, demonstrates highly selective agonism at mu-opioid receptors. The two endomorphins differ by a single amino acid but share similar receptor selectivity and analgesic properties.
Mechanism of Action
Endomorphin-2 is found in spinal and supraspinal sites involved in nociception. Its unique selectivity profile has generated interest in developing analogs that retain efficacy while minimizing respiratory depression and other opioid side effects.
Research Summary & Key Findings
Animal studies have confirmed potent analgesic activity of endomorphin-2 in thermal and inflammatory pain models following central administration. As with endomorphin-1, clinical utility is limited by rapid peptidase degradation and poor systemic bioavailability. Medicinal chemistry efforts have produced modified analogs with improved stability, though none have advanced to late-stage clinical trials.
Clinical Status
Endomorphin-2 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: "Endomorphin-2"
Peer-reviewed literature indexed by the National Library of Medicine.
- ClinicalTrials.gov: "Endomorphin-2"
Registered interventional and observational studies, including status and phase.
- PubChem: "Endomorphin-2"
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
Endomorphin-2 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.