Thymosin Alpha-1
Also known as Thymalfasin, Tα1, Zadaxin
Thymosin alpha-1 is a 28-amino-acid acetylated peptide originally isolated from calf thymus. It is studied as an immune modulator in chronic viral hepatitis, sepsis and infection, and as an adjunct to vaccines and cancer therapy.
Approved drug substance
Size
3 options- Catalog no.
- TA2
- Specification
- 2mg*10vials
- Per kit
- 10 vials
For laboratory research use only. Not for human or animal consumption. Buyers must be 21 or older.
Overview
Thymosin alpha-1 was isolated in the late 1970s by Allan Goldstein's group from thymosin fraction 5, a calf thymus extract, and corresponds to the N-terminal segment of the larger protein prothymosin alpha. The synthetic form, thymalfasin, is approved in a number of countries, including China, primarily for chronic hepatitis B; it is not approved by the US FDA. Laboratory work focuses on its effects on dendritic cells and T-cell function. Clinical research includes trials in hepatitis B and C, sepsis, and as an adjunct to vaccines and chemotherapy, with mixed results across indications.
Class: Thymic immunomodulatory peptide
Mechanism of action
How the compound acts, as described in the literature.
Acts on dendritic cells through MyD88-dependent Toll-like receptor signaling, with p38 MAPK and NF-κB activation, promoting maturation and interleukin-12 production in fungal infection models.
Associated with T-helper 1 polarization, T-cell maturation and enhanced antigen presentation in cell and animal studies.
In patients with severe sepsis, it was associated with faster recovery of monocyte HLA-DR expression, a marker of immune competence that is often suppressed in sepsis.
Published research
Selected studies, each linked to its PubMed record. Summaries describe what the studies reported.
2004
Mouse and in vitro study
PMID 14982877Thymosin alpha 1 activates dendritic cells for antifungal Th1 resistance through toll-like receptor signaling.
Romani L, et al. · Blood
Thymosin alpha-1 matured Aspergillus-pulsed dendritic cells and increased IL-12 production via MyD88-dependent Toll-like receptor signaling; in mice, including transplant recipients, it activated Th1 antifungal immunity and protected against aspergillosis.
2013
Multicenter RCT
PMID 23327199The efficacy of thymosin alpha 1 for severe sepsis (ETASS): a multicenter, single-blind, randomized and controlled trial.
Wu J, et al. · Crit Care
Among 361 patients with severe sepsis in six Chinese ICUs, 28-day mortality was 26.0% with thymosin alpha-1 versus 35.0% with control (nonstratified P = 0.062; log-rank P = 0.049), with greater monocyte HLA-DR recovery.
2025
Phase 3 RCT
PMID 39814420The efficacy and safety of thymosin α1 for sepsis (TESTS): multicentre, double blinded, randomised, placebo controlled, phase 3 trial.
Wu J, et al. · BMJ
In 1,089 adults with sepsis analyzed across 22 Chinese centers, 28-day mortality was 23.4% with thymosin alpha-1 and 24.1% with placebo (HR 0.99, P = 0.93); secondary and safety outcomes did not differ.
Evidence & safety
What the research does not show, and the adverse events and regulatory status it reports.
The largest sepsis trial (TESTS, phase 3) found no reduction in 28-day mortality, after the smaller single-blind ETASS trial reported a borderline result. In TESTS, safety outcomes did not differ from placebo, but exploratory subgroup analyses suggested possible differential effects by age and diabetes status, including a higher hazard in patients under 60, that did not meet the corrected significance threshold. Thymalfasin is approved in several countries but not by the US FDA.
Specifications
All sizes, exactly as catalogued.
| Catalog no. | Product | Specification | Vials per kit |
|---|---|---|---|
| TA2 | Thymosin Alpha-1 | 2mg*10vials | 10 |
| TA5 | Thymosin Alpha-1 | 5mg*10vials | 10 |
| TA10 | Thymosin Alpha-1 | 10mg*10vials | 10 |
For laboratory research use only. Not for human or animal consumption. Not intended to diagnose, treat, cure or prevent any disease. Research summaries are provided for educational purposes and do not describe this product’s use.