Thymosin Alpha-1
An immune-modulating thymic peptide approved in over 35 countries for hepatitis B and as an immune adjuvant, known for enhancing T-cell and dendritic cell function.
Also known as: Tα1, Thymalfasin, Zadaxin
Regulatory Status
Classification date: 2026-02-27
Reclassification to Category 1 announced but not yet formalized
Compounding: Not currently available for compounding
Evidence Summary
How It Works
Thymosin alpha-1 is a 28-amino-acid peptide originally isolated from thymus tissue. It stimulates maturation of T-cells from bone marrow progenitors, enhances dendritic cell antigen presentation, and activates natural killer cell cytotoxicity via Toll-like receptor signaling. It modulates the balance between Th1 and Th2 immunity, shifting toward a Th1-dominant response. It is approved outside the US for chronic hepatitis B and C and as an adjunct to chemotherapy and vaccines.
Common Applications
Safety & Considerations
Excellent safety profile demonstrated across multiple clinical trials and decades of use in over 35 countries. The most common side effect is mild injection-site discomfort. No significant drug interactions reported. Caution is warranted in patients with organ transplants on immunosuppressive therapy, as immune activation could trigger rejection.
Related Research
Regulatory classifications can change rapidly. The information shown here was last verified on 2026-02-27. Always confirm current legal status with a licensed provider or the FDA before making treatment decisions.