# Thymosin Alpha-1

> Thymus-derived 28-amino-acid peptide approved in many countries as an immunomodulator.

- Also known as: Tα1, Thymalfasin, Zadaxin
- Class: Immune
- FDA approved: No
- Canonical page: https://www.americanpeptide.com/catalog/thymosin-alpha-1

## Overview

Thymosin α1 is a 28-amino-acid peptide originally isolated from thymic tissue. Approved in numerous countries as adjunctive therapy in chronic hepatitis B / C and as an immune-system modulator.

Thymosin alpha-1 (Tα1, thymalfasin) is a 28-amino-acid peptide originally isolated from the thymus, the organ where T cells mature. It acts as an immune modulator, helping to restore and direct T-cell responses.

Unlike most catalogued peptides, Tα1 is approved in many countries (marketed as Zadaxin) as an adjunct in chronic hepatitis B and C and in other immune contexts, though it is not FDA-approved in the United States. It is among the most clinically studied immunomodulatory peptides.

## Mechanism

TLR9-mediated DC activation; Th1 immune polarization.

## Chemistry

| Property | Value |
| --- | --- |
| Molecular formula | C129H215N33O55 |
| Molecular weight | 3108.3 Da |
| CAS number | 62304-98-7 |
| PubChem CID | [16130571](https://pubchem.ncbi.nlm.nih.gov/compound/16130571) |

## Sequence

```
SDAAVDTSSEITTKDLKEKKEVVEEAEN
```

## Research areas

Studied in: Chronic viral hepatitis, Sepsis adjunct, Oncology adjunct.

Guides on this site:

- [Immune & Inflammation](https://www.americanpeptide.com/research-areas/immune-inflammation): Thymic and host-defense peptides studied for immune modulation.

## Key research

- T-cell modulation — TLR9-mediated dendritic-cell activation and Th1 polarization.
- Chronic viral hepatitis — adjunctive use studied and approved in many countries.
- Sepsis — examined as an immune-restoring adjunct.
- Oncology — studied as an adjunct to support immune response.
- Approved abroad — marketed as Zadaxin; not FDA-approved in the US.

## FAQs

### What is Thymosin alpha-1?

Thymosin alpha-1 is a thymus-derived immunomodulatory peptide (Zadaxin) used in many countries as an adjunct in chronic hepatitis and other immune conditions.

### How does it work?

It supports and directs T-cell responses, in part through TLR9-mediated dendritic-cell activation and a shift toward Th1 immunity.

### Is it FDA-approved?

It is approved in numerous countries but not by the US FDA. This page is a research and educational reference.

### What is it studied for?

Chronic viral hepatitis, and as an immune-supporting adjunct in sepsis and oncology research.

## Latest research

Recent trials and publications mentioning Thymosin Alpha-1, pulled automatically from ClinicalTrials.gov and PubMed (unfiltered search results, refreshed daily).

### Recent trials

- [Neoadjuvant Chemoradiotherapy Combined With PD-1 Inhibitor and Thymalfasin for Locally Advanced Mid-low Rectal Cancer](https://clinicaltrials.gov/study/NCT06024356) — COMPLETED · NCT06024356
- [Thymosin Alpha 1 Combined With Anti-PD-1 Monoclonal Antibody in Elderly Patients With Advanced Melanoma](https://clinicaltrials.gov/study/NCT07644897) — RECRUITING · PHASE2 · NCT07644897
- [TPF Concurrent Chemo-radiotherapy Plus Immunotherapy for Local Advanced Esophageal Squamous Cell Carcinoma](https://clinicaltrials.gov/study/NCT06401447) — ACTIVE_NOT_RECRUITING · NA · NCT06401447
- [Thymosin Alpha 1 to Prevent COVID-19 Infection in Renal Dialysis Patients](https://clinicaltrials.gov/study/NCT04428008) — COMPLETED · PHASE2 · NCT04428008
- [Phase II Trial of Neoadjuvant Thymalfasin, PD-1 Inhibitor, and Chemoradiotherapy for cStage III GEJ Adenocarcinoma](https://clinicaltrials.gov/study/NCT07277439) — RECRUITING · PHASE2 · NCT07277439
- [Efficacy and Safety of Anti-PD-1, Thymalfasin, and SOX in Neoadjuvant Treatment of cStage III Gastric/Gastroesophageal Junction Adenocarcinoma](https://clinicaltrials.gov/study/NCT06461910) — RECRUITING · PHASE2 · NCT06461910

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Source: AmericanPeptide.com — https://www.americanpeptide.com/catalog/thymosin-alpha-1
Data license: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Attribution: AmericanPeptide.com.
Research reference only — computational and educational content, not medical advice.