Thymosin Alpha-1
Stronger clinical signalAlso known as: Zadaxin · Thymalfasin · Tα1
A 28-amino-acid immunomodulatory peptide, marketed in dozens of countries as Zadaxin/thymalfasin for chronic viral hepatitis and as an immune-response adjunct in cancer and infection. One of the few peptides in this space with genuine international drug-approval history.
Mechanism (plain language)
Promotes maturation and function of T-cells and enhances antigen-presenting cell activity, supporting broader antiviral and antitumor immune responses without being a direct antimicrobial or cytotoxic agent itself.
What research suggests
Randomized trials in chronic hepatitis B (alone and combined with interferon) report improved viral suppression and liver-function normalization; a further RCT in HBV-related acute-on-chronic liver failure reported improved transplant-free survival. Broader use spans cancer adjuvant therapy and immune deficiency contexts internationally.
Uncertainties & risks
Approved abroad but not FDA-approved in the US as a prescription drug; most large trials are in specific hepatology/oncology populations, not healthy individuals seeking general immune support. Response rates in some hepatitis trials were moderate (around 50%), and combination-therapy questions remain open.
Primary sources
Secondary citations for verification. Prefer the STACKD summary above for context before opening these.
- Zadaxin (thymosin alpha1) for the treatment of viral hepatitis
2005 · review
Review of clinical trials showing efficacy in chronic hepatitis B and, combined with interferon, in hepatitis C.
- Safety and efficacy of Thymosin α1 in the treatment of hepatitis B virus-related acute-on-chronic liver failure: a randomized controlled trial
2022 · human
RCT of 120 patients found significantly higher 90-day transplant-free survival with Tα1 versus standard therapy alone.