Thymosin Alpha-1
Thymalfasin · 28-residue thymic peptide
An endogenous thymic peptide acting as a Toll-like receptor agonist, studied in large randomised trials in sepsis and chronic hepatitis B.
Thymosin alpha-1 is cleaved from prothymosin alpha and acts principally through TLR2 and TLR9 on dendritic cells and monocytes. It has among the strongest human clinical evidence bases of any compound in this catalog, including a 2025 phase 3 trial published in the BMJ.
It is not approved by the FDA — a Drugs@FDA search returns no record under thymalfasin or thymosin alpha-1 — though it is approved and marketed as Zadaxin in a number of other countries.
Specification
| CAS number | 62304-98-7 |
|---|---|
| Molecular formula | C129H215N33O55 |
| Molecular weight | 3108.3 g/mol |
| Purity | ≥98% (HPLC) |
| Sequence | Ac-SDAAVDTSSEITTKDLKEKKEVVEEAEN |
| Appearance | Lyophilised white powder |
| Storage | Store at -20°C, protect from light |
Batch records & certificates
Every lot we hold of this compound, across all warehouses. The certificate is tied to that lot number — not a generic sample document.
| Lot | Warehouse | Purity | Tested | Laboratory | Documents |
|---|---|---|---|---|---|
| TA25-0094 | India | 98.6% | 29 Jun 2026 | Colmaric Analyticals | COA pending |
| TA25-0088 | United Kingdom | 98.5% | 8 May 2026 | Janoshik Analytical | COA pending |
Published research
Full research profileIn human clinical trials
The efficacy of thymosin alpha 1 for severe sepsis (ETASS): a multicenter, single-blind, randomized and controlled trial
A multicentre randomised controlled trial reporting reduced 28-day mortality in severe sepsis.
The efficacy and safety of thymosin α1 for sepsis (TESTS): multicentre, double blinded, randomised, placebo controlled, phase 3 trial
A large phase 3 placebo-controlled trial — the most rigorous evidence available for this compound.
Efficacy of thymosin alpha1 in patients with chronic hepatitis B: a randomized, controlled trial
Randomised controlled trial in chronic hepatitis B reporting sustained response at follow-up.