▶ THYMOSIN Α-1 · SUBTOPIC · MECHANISM

THYMOSIN α-1 Mechanism

For Laboratory Research Use Only. The mechanistic information below is descriptive of published research. No human dose is recommended. No clinical claim is made.

MECHANISM OF ACTION

Twenty-eight-amino-acid peptide cleaved from prothymosin-alpha in the thymus gland. Marketed as Zadaxin in EU and Asia for chronic hepatitis B/C and immune dysfunction. FDA orphan drug status. Modulates TLR9 signaling and drives T-cell + NK-cell activity.

PHARMACOKINETIC HALF-LIFE

Reported half-life for THYMOSIN α-1: ~2 hours plasma (subcutaneous). Half-life determines the kinetic window across which receptor occupancy is maintained and frames the dosing rhythm used in published literature.

PRIMARY SEQUENCE

THYMOSIN α-1 is a defined 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. Synthesis proceeds via solid-phase peptide synthesis with HPLC-verified identity confirmation.

MECHANISTIC OUTCOMES IN LITERATURE

The following outcomes are the mechanistic endpoints reported in the peer-reviewed literature, with GIGARESEARCH evidence grades. Grades reflect study quality and replication, not clinical recommendation.

▶ Chronic hepatitis B (Asia, approved use)GRADE A

Multiple Phase 3 trials supporting Zadaxin approval in 35+ countries as combination therapy with IFN/pegIFN.

▶ Sepsis (Chinese Phase 3)GRADE B

Wu 2013 Crit Care · 28-day mortality reduction in severe sepsis.

▶ COVID-19 severity (Chinese reports)GRADE C

Multiple Chinese-population reports; not consistently meeting Western trial methodology.

MECHANISM Q+A

▶ How does it work?

Proposed mechanisms include TLR9 agonism, dendritic-cell maturation, increased CD4+ and CD8+ T-cell function, enhanced NK cell activity, and modulation of Th1/Th2 cytokine balance toward Th1.

CITED LITERATURE

Goldstein AL, Goldstein AL. From lab to bedside: emerging clinical applications of thymosin alpha 1. Expert Opin Biol Ther 2009. PMID 19392576. link
Wu J, Zhou L, Liu J, et al.. The efficacy of thymosin alpha 1 for severe sepsis (ETASS): a multicentre, single-blind, randomized and controlled trial. Crit Care 2013. PMID 23327199. link
Liu Y, Pan Y, Hu Z, et al.. Thymosin Alpha 1 Reduces the Mortality of Severe Coronavirus Disease 2019. Clin Infect Dis 2020. PMID 32442287. link

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▶ LAST UPDATED · 2026-05-19