Leu-Enkephalin
Leucine Enkephalin (Tyr-Gly-Gly-Phe-Leu)
An endogenous opioid pentapeptide with significant immunomodulatory properties at the neuro-immune interface. Leu-Enkephalin modulates NK cell activity, T-cell function, and inflammatory cytokine production, representing a key link between the nervous system and immune regulation.
Mechanism of Action
Leu-Enkephalin acts on delta (δ) and mu (μ) opioid receptors expressed on immune cells including NK cells, T-lymphocytes, macrophages, and dendritic cells. At low doses it enhances NK cell cytotoxicity and T-cell proliferation; at higher doses it may suppress immune activation. It inhibits pro-inflammatory cytokine production (TNF-α, IL-1β) via opioid receptor-mediated cAMP suppression and modulates macrophage phagocytic activity. It also acts centrally to reduce pain perception and stress-induced immunosuppression. Its role in neuro-immune communication makes it relevant for conditions where chronic stress or pain drives immune dysregulation.
Health Claims & Evidence
Enhances NK cell cytotoxicity and anti-tumor immune surveillance
Reduces pro-inflammatory cytokine production
Modulates T-cell proliferation and immune balance
Reduces stress-induced immunosuppression via neuro-immune axis
Anti-nociceptive — reduces inflammatory pain
Short-Term Effects
Reduced inflammatory pain, enhanced NK cell activity, improved immune response, stress relief.
Long-Term Effects
Improved neuro-immune balance, sustained NK cell function, reduced chronic inflammatory pain.
Side Effects
Mild sedation at higher doses. Potential for receptor desensitization with continuous use — cycling essential. No addiction risk at peptide doses.
Contraindications
Caution with concurrent opioid medications. Avoid in individuals with opioid receptor hypersensitivity. Do not combine with opioid antagonists.
This profile is provided for educational research only. It is not a treatment recommendation or dosing guide. Human evidence, safety information and regulatory status vary by substance. Verify primary sources and consult a qualified healthcare professional for medical decisions.
Research Papers
Opioid peptides and immune function: a review
Wybran J · Journal of Immunology · 1985
Enkephalins modulate NK cell activity
Mandler RN et al. · Journal of Immunology · 1986
Neuro-immune interactions of endogenous opioid peptides
Plotnikoff NP et al. · Annals of the New York Academy of Sciences · 1994
Educational research only. This profile is not a treatment recommendation or dosing guide. Human evidence, safety information and regulatory status vary by substance. Consult a qualified healthcare professional for medical decisions.
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