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Thymosin Alpha-1

low risk

Also: Tα1 · Thymalfasin · Zadaxin

Strong Evidence FDA Approved

Thymosin Alpha-1 is one of the most clinically validated immune peptides. Approved as Zadaxin in 35+ countries for hepatitis B/C and cancer immunotherapy. Meta-analysis of 7 RCTs shows significant mortality reduction in sepsis. Gold standard immune peptide.

Molecular Weight
3108.3 Da
Formula
C129H215N33O55
Common Dosing
1.6 mg SC twice weekly (standard); 3.2 mg/day in acute sepsis protocols
Category
therapeutic
Last Reviewed
2025-01-15

Reported Benefits

Hepatitis B treatment

Strong Evidence 89 studies

Approved in 35 countries. Multiple RCTs: HBV DNA suppression and seroconversion.

Sepsis mortality reduction

Moderate Evidence 28 studies

Meta-analysis (7 RCTs): significant 30-day mortality reduction, especially in immunosuppressed phenotype.

COVID-19 severity reduction

Moderate Evidence 19 studies

Chinese RCT (2021): reduced progression to severe disease and mortality.

Mechanism of Action

Activates dendritic cells, T-helper cells, NK cells; upregulates MHC I/II; increases IL-2 and IFN-γ; modulates Toll-like receptors; thymic T-cell maturation.

Key Clinical Studies

Shrivastava et al. (2022)

Meta-analysis · Meta-analysis (7 RCTs)

PubMed →

Significant reduction in 28-day sepsis mortality (OR 0.50)

Liu et al. (2021)

RCT · n=127

PubMed →

Reduced severe COVID-19 progression and ICU admission

The Immunology Gold Standard

Among all immune-modulating peptides in this database, Thymosin Alpha-1 has the most extensive and credible human evidence. This is the benchmark against which other “immune peptides” should be measured.

Immunosenescence

Growing application in elderly patients with age-related immune decline. Studies suggest partial restoration of thymic output and T-cell diversity — relevant to infection susceptibility and vaccine response in older adults.

Regulatory Status

FDA Approved

Approved in 35+ countries (Zadaxin). 503A listed for US compounding.

Safety Profile

Side Effects

  • Injection site reactions
  • Mild fatigue
  • Transient flu-like symptoms

Contraindications

  • Active autoimmune disease
  • Organ transplant on immunosuppression

Drug Interactions

  • Immunosuppressants (opposing effects)

Primary Uses

Immune enhancementHepatitis B treatmentSepsis adjunctCancer immunotherapy adjunct

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Disclaimer: This information is for educational and research purposes only. Not medical advice. Consult a qualified healthcare provider before using any compound.