Thymulin
Thymulin (Facteur Thymique Sérique) is an incredibly potent, zinc-dependent nonapeptide and the only known circulating thymic hormone. Exclusively produced by thymic epithelial cells in youth, its production crashes essentially to zero following post-pubescent thymic involution. Exogenous Thymulin administration is an elite, bleeding-edge protocol utilized to forcefully re-engage T-cell immunity, dramatically spike aggressive Natural Killer (NK) cell counts, and combat severe autoimmune and immunodeficient states.
Quick Stats
Scientific Data
Mechanism of Action
Thymulin (Facteur Thymique Sérique / FTS) is a 9-amino-acid thymic peptide that requires zinc binding to be biologically active. It is produced by thymic epithelial cells and is a key mediator of T-cell differentiation and maturation, specifically promoting CD4/CD8 T-cell development and NK cell activity.
Thymulin levels decline markedly with age and zinc deficiency — both reduce immune competence. Thymulin supplementation (either as the peptide or via zinc repletion to restore endogenous activity) has been studied for immune senescence, cancer immunotherapy support, and inflammatory disease. It is a member of the Khavinson bioregulator peptide family, representing a complementary approach to Thymalin.
Source: PMID: 3299395
Background & History
Thymulin (FTS) was discovered by Jean-François Bach and Mireille Dardenne at Hôpital Necker in Paris (1977). It was the first — and remains the only — thymic hormone found in circulating blood. This makes it the immune system's equivalent of insulin or thyroxine: a measurable hormone that declines with age and whose deficiency has demonstrated clinical consequences. The discovery that thymulin requires zinc for biological activity (1980) was a landmark finding linking trace mineral nutrition to immune function.
Research Use Cases
- ✓Immune reconstitution after thymic involution
- ✓Zinc-thymulin immunotherapy research
- ✓Immunosenescence biomarker (serum levels indicate thymic function)
- ✓Anti-aging immune protocols targeting thymic restoration
Dosing Protocol
| Typical Dose | 1-5 mg/day |
| Frequency | 1× daily for 10-30 day cycles |
| Half-Life | ~30 minutes (estimated) |
| Common Vial Sizes | 5 mg, 10 mg |
Dosing Protocols
Immune Support Protocol
Body-Weight Dosing Reference
Estimated doses extrapolated from the published research range of 1000–5000 mcg/day (referenced to 70 kg / 154 lb). These are approximations — consult a qualified healthcare provider for personalised guidance.
| Weight | Low Dose | Target Dose | High Dose |
|---|---|---|---|
| 120 lb(54 kg) | 771 mcg | 2314 mcg | 3857 mcg |
| 140 lb(63 kg) | 900 mcg | 2700 mcg | 4500 mcg |
| 160 lb(73 kg) | 1043 mcg | 3129 mcg | 5214 mcg |
| 180 lb(82 kg) | 1171 mcg | 3514 mcg | 5857 mcg |
| 200 lb(91 kg) | 1300 mcg | 3900 mcg | 6500 mcg |
| 220 lb(100 kg) | 1429 mcg | 4286 mcg | 7143 mcg |
| 250 lb(113 kg) | 1614 mcg | 4843 mcg | 8071 mcg |
💉 For exact syringe units based on your vial concentration, use the Thymulin Reconstitution Calculator →
Administration
Expected Timeline
Who Is It For?
Immune Senescence
LowRestores thymic peptide signaling in aged immune systems. Works synergistically with zinc repletion.
T-Cell Immunology
LowMediates T-cell differentiation and maturation. Research-level use in cancer immunotherapy support.
Reconstitution Example
Safety & Considerations
Research peptide. Active only when bound to zinc. Ensure zinc sufficiency for full activity. Very low doses used. No significant toxicity reported in research studies.
Regulatory & Legal Status
Not currently on the WADA 2026 Prohibited List. Policies may change — verify before competition.
Research Chemical
US Compounding: Not eligible / not available
⚠️ This information is for educational purposes only and may not reflect the most current regulatory updates. Always verify with official FDA, WADA, and jurisdiction-specific sources before use.
Interactions & Contraindications
REQUIRES zinc supplementation for biological activity — Zn-thymulin complex is the active form. May overstimulate immune system in autoimmune conditions. Not to be combined with immunosuppressive drugs without supervision. Well-characterized safety across decades of research.
Synergies & Common Stacks
Thymulin (circulating thymic hormone) + Thymalin (thymic polypeptide extract) provide complementary thymic support through different mechanisms — Thymulin acts systemically, Thymalin acts directly on thymic tissue.
Thymulin (immune hormone) + Vilon (synthetic thymic dipeptide bioregulator) target immune function through different molecular pathways — circulating hormone vs. epigenetic gene regulation.
Dosing Quick Reference
Frequently Asked Questions
Does thymulin require zinc?▼
How does thymulin differ from thymalin?▼
References
- Dardenne M, Bach JF “"Thymulin: a thymic factor for immune development".” Annals of the New York Academy of Sciences (1975). PMID: 1060378
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