Thymosin Alpha-1

Thymosin Alpha-1 (Tα1) is a 28-amino-acid peptide naturally secreted by the thymus. It is one of the most clinically researched peptides in oncology — licensed in over 35 countries as Zadaxin® for use alongside cancer chemotherapy and as an antiviral. It restores immune competence in immunosuppressed patients, particularly those undergoing cytotoxic treatment.

Properties

Amino Acid Sequence

Ac-Ser-Asp-Ala-Ala-Val-Asp-Thr-Ser-Ser-Glu-Ile-Thr-Thr-Lys-Asp-Leu-Lys-Glu-Lys-Lys-Glu-Val-Val-Glu-Glu-Ala-Glu-Asn-OH

Origin: Naturally produced by the thymus gland; synthetic analogue

Tα1 binds to Toll-Like Receptors (TLR2 and TLR9) on dendritic cells and T-lymphocytes, triggering a cascade that increases IL-2, interferon-α, and NK cell cytotoxicity. It shifts immune response from an exhausted Th2 phenotype toward an active Th1 anti-tumour phenotype. Also activates dendritic cell maturation and suppresses immunological tolerance that tumours exploit.

Used clinically in Italy, China, and Southeast Asia alongside chemotherapy and radiation to reduce immunosuppression, restore T-cell counts after treatment, reduce treatment-related infections, and improve quality of life. Studies in hepatocellular carcinoma, lung, melanoma, and non-Hodgkin lymphoma show improved response rates and survival when added to standard care. Reduces chemotherapy-related mortality from infection.

Links open on PubMed (National Library of Medicine). Research is ongoing — results may not reflect clinical use.

• Requires subcutaneous injection — sterile technique essential
• May be contraindicated with organ transplant immunosuppression
• Not a standalone cancer treatment — adjunctive only
• Not approved by FDA (available as research peptide in US); licensed as Zadaxin in 35+ countries
• Refrigerate at 2–8°C; do not freeze reconstituted solution