Thymulin
FTS Β· Facteur Thymique SΓ©rique Β· Serum Thymic Factor
Zinc-dependent nonapeptide secreted exclusively by thymic epithelial cells. Distinct from Thymosin Alpha-1 β thymulin directly promotes T-cell maturation and differentiation within the thymus. Its production declines sharply with age and thymic involution.
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Mechanism of Action
Thymulin binds zinc as an obligate cofactor; the Zn-thymulin complex is the biologically active form. Induces expression of T-cell markers (CD3, CD4, CD8) on immature thymocytes, promotes T-helper/T-suppressor differentiation, and enhances NK cell activity. Plasma levels are a direct biomarker of thymic functional reserve.
Clinical Applications
- βAge-related immune decline and immunosenescence
- βPost-viral immune reconstitution
- βT-cell deficiency states
- βAutoimmune modulation (adjunctive, with caution)
- βCombined immunodeficiency support
Dosing Protocol
Recommended Dosing
SC injection. 20β50 mcg/day for 5 days (induction), then 10β20 mcg 3x/week (maintenance). Zinc supplementation (15β30 mg elemental zinc/day) is essential to ensure peptide activation. Cycle: 4β6 weeks, then reassess immune markers.Safety & Contraindications
Possible Side Effects
- β Mild injection-site irritation
- β Transient lymphocytosis (expected β reflects immune activation)
Contraindications
- βActive autoimmune disease (may amplify autoreactive T-cell responses)
- βOrgan transplant recipients on immunosuppression
- βHaematological malignancies involving T-cell lineage