COMPOUND

Compounds / Immune

Thymosin Alpha-1

Thymosin Alpha-1 (Thymalfasin / Zadaxin)

Immune SubQ Compoundable (FDA Cat. 1)

28-amino-acid peptide fragment of prothymosin alpha. Licensed in 35+ countries for hepatitis B/C and as an immune adjuvant; not FDA-approved in the US. The most heavily researched immunomodulatory peptide.

At a glance

Half-life
~2 h ~2h serum t½ after SC injection. Biological effect persists longer than plasma levels via downstream immune-cell activation.
Routes
SubQ
Evidence base
2 studies 1 human · 1 review

Mechanism

Binds TLR-9 (and possibly TLR-2) on dendritic cells and T-cells, restoring balanced Th1/Th2 response. Drives CD8+ cytotoxic T-cell maturation, modulates regulatory T-cell output, and restores antigen-presenting cell function, particularly useful in immune-senescent or chronically infected states.

Dosing

Any amounts shown here are reported from published studies only. 1 of 2 catalogued studies involved human subjects. COMPOUND does not publish its own dosing guidance.

Published evidence

  1. Human observational 2020

    Thymosin alpha 1 reduces the mortality of severe coronavirus disease 2019 by restoration of lymphocytopenia and reversion of exhausted T cells

    Liu Y, Pan Y, Hu Z, et al. Clin Infect Dis

    Small retrospective Wuhan cohort (n=76, first wave). TA-1 vs untreated: mortality 11.1% vs 30.0% (p=.044) with restored CD4/CD8 counts. Later larger studies and meta-analyses have been mixed; not established treatment.

    PMID 32442287

  2. Review 2015

    Historical review of thymosin α 1 in infectious diseases

    Camerini R, Garaci E. Expert Opin Biol Ther

    TA-1 has a 30-year safety record; efficacy demonstrated in chronic hepatitis B/C adjunct therapy, sepsis, and aspergillosis prophylaxis post-BMT.

    PMID 26098768

Reported side effects

Injection site reaction
Occasional Mild · Transient redness or mild discomfort.
Transient flu-like symptoms
Rare Mild · Brief immune activation can cause mild myalgia, malaise for a few hours post-dose; resolves same day.

Reconstitution and storage

Lyophilized powder. Reconstitute with BAC water. Typical: 1mL BAC per 1.6mg vial = 1.6 mg/mL. Gentle swirl.

Lyophilized: refrigerate 2-8°C. Reconstituted: refrigerate, use within 14-30 days. Protect from light.

Open the reconstitution calculator for Thymosin Alpha-1