The Peptide Audit

What is Thymosin Alpha-1?

Human clinical studiesImmune research · Last reviewed September 28, 2026

Thymosin alpha-1 is a 28-amino-acid peptide originally isolated from the thymus, the organ where immune T-cells mature.

How does Thymosin Alpha-1 work?

It acts on immune cells through toll-like receptors and has been shown to influence T-cell maturation and the body’s response to infection.

What are researchers studying?

Where does the evidence stand?

Human clinical studies

Approved as a drug (thymalfasin, Zadaxin) in several countries outside the U.S. Not approved by the FDA.

Quick facts

Research area
Immune
Also known as
TA1, Ta-1, Thymosin Alpha 1
Third-party lab results
3 published COAs →
Tested vendors tracking it
2 vendors →

Recent peer-reviewed research

The most relevant Thymosin Alpha-1 studies from the last three years, via PubMed (U.S. National Library of Medicine).

  1. The efficacy and safety of thymosin alpha-1 combined with lenvatinib plus sintilimab in unresectable hepatocellular carcinoma: a retrospective study
    Scientific reports · 2025 Apr 22 · PubMed ↗
  2. Exploiting the potential of in situ forming liquid crystals: development and in vitro performance of long-acting depots for peptide drug thymosin alpha 1 subcutaneous administration
    Drug delivery · 2025 Dec · PubMed ↗
  3. Phenotypic drug discovery: a case for thymosin alpha-1
    Frontiers in medicine · 2024 · PubMed ↗
  4. Immune-Enhancing Treatment among Acute Necrotizing Pancreatitis Patients with Metabolic Abnormalities: A Post Hoc Analysis of a Randomized Clinical Trial
    Gut and liver · 2024 Sep 15 · PubMed ↗
  5. Thymosin Alpha-1 Provides Direct Neuroprotection by Engaging the Orexin Receptor HCRTR1 to Suppress Neuronal Necroptosis
    Advanced science (Weinheim, Baden-Wurttemberg, Germany) · 2026 Sep 3 · PubMed ↗

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This guide summarizes published research for educational purposes only. It is not medical advice and does not describe how to use Thymosin Alpha-1. Citations link to PubMed and are listed for reference — we haven't reviewed or endorsed their findings. Products referenced on The Peptide Audit are sold by third parties for laboratory research use only and are not for human consumption.