Thymulin
Also known as: Facteur Thymique Sérique, FTS, Serum Thymic Factor, Zinc-Thymulin, Zn-FTS
FTS | Zinc-Dependent Thymic Nonapeptide
Overview
Thymulin is a nonapeptide hormone exclusively secreted by thymic epithelial cells, discovered by Jean-François Bach in the 1970s. Unlike thymalin (a peptide extract mixture), thymulin is a single, defined 9-amino-acid peptide that requires zinc binding for biological activity. It plays a crucial role in T-cell differentiation and maturation within the thymus. Serum thymulin levels decline significantly with age and zinc deficiency, contributing to age-related immune decline (immunosenescence). Research has explored thymulin's potential in restoring immune function, managing autoimmune conditions, and as an anti-inflammatory agent.
Key benefits
- Essential for T-cell maturation and differentiation
- Modulates immune responses (immunomodulatory)
- Anti-inflammatory properties
- Declines with age - restoration may combat immunosenescence
- Well-defined single peptide (unlike extracts)
- Studied in autoimmune disease research
- Neuroendocrine regulatory effects
- Zinc-dependent activity allows for regulation
Mechanism of action
Thymulin exerts its effects through binding to high-affinity receptors on T-lymphocytes and other immune cells. The zinc-thymulin complex is the biologically active form - without zinc, the peptide has no immunological activity. Thymulin promotes: (1) differentiation of immature T-cells into mature T-cell subsets, (2) modulation of cytokine release including IL-2 and interferon-gamma, (3) regulation of T-helper and T-suppressor cell balance, (4) enhancement of NK cell activity, and (5) anti-inflammatory effects through suppression of pro-inflammatory mediators. It also has neuroendocrine effects, influencing the hypothalamic-pituitary-adrenal axis.
Molecular data
- Type
- Thymic nonapeptide hormone
- Half-life
- ~10 minutes (free form); extended with nanoparticle formulations
Sequence
pGlu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn (pyro-Glu N-terminus)
Indications
What the research community uses this compound for, with self-reported effectiveness.
Immune System Research
Inflammatory & Autoimmune Research
Neuroendocrine Research
Dosing protocols
Common protocols by delivery method. Adjust the curve below to model accumulation in your own cycle.
Delivery method
| Protocol | Dose | Frequency | Duration |
|---|---|---|---|
| — | 1-10 mcg | Daily | — |
| — | Variable | As studied | — |
Safety
Reported adverse effects, contraindications, and what to monitor on cycle.
Common side effects
- Generally well-tolerated in research
- Injection site reactions (mild)
Rare side effects
- Allergic reactions
- Immune modulation effects
Contraindications
- Autoimmune diseases (use with medical supervision)
- Organ transplant recipients on immunosuppression
- Pregnancy or breastfeeding
- Known hypersensitivity to thymic peptides
Monitoring
- Zinc status should be adequate
- Immune function panels if available
- T-cell subsets if monitoring research outcomes