Thymulin
Thymulin (Facteur Thymique SΓ©rique)
The thymus peptide that declines with immune aging
Thymulin is a nonapeptide hormone produced by the thymus gland, essential for T-cell maturation and immune regulation. Levels decline dramatically with thymic involution.

Admin routes
Subcutaneous
Popularity
Niche
Side effects
Generally mild
AU vendors
0 rated
βKey benefits
πWhat to expect
Immune system activation begins
Enhanced T-cell maturation and NK cell activity
Improved immune markers; reduced infection susceptibility
Full immune restoration benefits; consider cycling
Based on community reports and published research. Individual results vary significantly.
πDosing protocols
Immune support
50β100 mcg
Once daily
4β8 week cycles
Immune restoration
100 mcg
Once daily
8β12 weeks
Dosing information is sourced from published research and community protocols. This is not a recommendation. Consult a healthcare professional.
Research status|Clinical data available - studied since the 1970s
Overview
Thymulin (also known as FTS - Facteur Thymique SΓ©rique) is a nine-amino-acid peptide hormone produced by thymic epithelial cells. It requires zinc as a cofactor and is essential for T-cell differentiation, maturation, and immune regulation. Thymulin levels decline sharply after puberty as the thymus involutes (shrinks), contributing to the age-related decline in immune function known as immunosenescence.
βοΈHow it works
Binds to specific receptors on T-cell precursors, promoting their maturation into functional T-cells (CD4+ and CD8+). Modulates cytokine production, enhances NK cell activity, and regulates the balance between pro- and anti-inflammatory immune responses. Requires zinc to adopt its biologically active conformation - without zinc, thymulin is inactive.
β‘Side effects
π Research history
Thymulin (FTS) characterised by Jean-FranΓ§ois Bach in Paris
Zinc dependence of thymulin established
Role in immunosenescence and thymic involution clarified
Gene therapy approaches to restore thymulin levels explored
Interest renewed alongside growing focus on immune aging
Thymic involution and aging
The thymus is most active during childhood and adolescence, when it trains the immune system by producing mature T-cells. After puberty, it progressively shrinks (involutes) and is largely replaced by fatty tissue. By age 50, thymulin production has declined by 90%+. This contributes to increased infection susceptibility, reduced vaccine response, and higher cancer risk in older adults. Thymulin replacement aims to partially restore this lost immune education function.
References
- [1]Bach JF. 'Thymulin (FTS-Zn).' Clinics in Immunology and Allergy, 1983.
- [2]Reggiani PC, et al. 'Thymulin gene therapy and anti-aging.' Biogerontology, 2014.
Frequently asked questions
Related peptides
Community experiences
Share your experience with Thymulin. Effects, side effects, protocol details - help others make informed decisions.
No community reviews yet. Be the first to share your experience with Thymulin.
Need to calculate your dose?
Use our free reconstitution calculator to work out syringe units for Thymulin.
Open CalculatorDisclaimer: This guide is for educational and informational purposes only. It is not medical advice. The dosing protocols listed are sourced from published research and community reports and do not constitute a recommendation. Always consult a qualified healthcare professional before using any peptide. Australian regulations classify many peptides as Schedule 4 (prescription-only) substances. Check current TGA guidelines before purchasing.