All peptide guides
Immune Support

Thymosin Alpha-1

Immune-Modulating Peptide - Clinical Monograph

Clinical Disclaimer: This guide is for educational purposes only and does not constitute medical advice. Prescribers should exercise independent clinical judgment and verify all information before making treatment decisions.

What is Thymosin Alpha-1?

Thymosin Alpha-1 (Ta1) is a 28-amino acid peptide originally isolated from the thymus gland. It plays a crucial role in T-cell maturation and immune regulation. A synthetic version is approved in multiple countries for hepatitis B and C and is available through compounding in the United States.

Amino Acid Sequence: Ac-Ser-Asp-Ala-Ala-Val-Asp-Thr-Ser-Ser-Glu-Ile-Thr-Thr-Lys-Asp-Leu-Lys-Glu-Lys-Lys-Glu-Val-Val-Glu-Glu-Ala-Glu-Asn

Mechanism of Action

T-Cell Modulation

  • Promotes T-cell maturation and differentiation
  • Enhances T-helper cell function (Th1 response)
  • Restores T-cell populations in immunocompromised states

Dendritic Cell Activation

  • Stimulates dendritic cell maturation
  • Enhances antigen presentation
  • Bridges innate and adaptive immunity

Cytokine Modulation

  • Increases IL-2 and interferon-gamma
  • Modulates inflammatory cytokine balance
  • Supports appropriate immune responses

Toll-Like Receptor Signaling

  • Acts through TLR2 and TLR9 pathways
  • Enhances pathogen recognition
  • Supports innate immune responses

Clinical Applications

Approved Indications (Outside US)

  • Chronic hepatitis B
  • Chronic hepatitis C
  • Adjunct cancer immunotherapy
  • Vaccine adjuvant

Clinical Use Considerations (US)

  • Immune support in chronic infections
  • Adjunctive therapy in certain cancers (with oncologist supervision)
  • Post-chemotherapy immune recovery
  • Chronic viral conditions
  • Recurrent infections

Dosing Protocols

Standard Dosing

  • Typical dose: 1.6 mg (1600 mcg) subcutaneously
  • Frequency: 2-3 times weekly
  • Duration: 2-6 months depending on indication

Condition-Specific Approaches

Immune Support:

  • 1.6 mg twice weekly for 4-12 weeks

Chronic Infections:

  • 1.6 mg 2-3 times weekly for 6-12 months

Oncology Adjunct:

  • Per oncologist protocol, often 1.6 mg daily during treatment cycles

Patient Selection Criteria

Good Candidates

  • Recurrent viral or bacterial infections
  • Chronic viral hepatitis
  • Post-chemotherapy immune recovery (with oncologist approval)
  • Documented T-cell deficiency or dysfunction
  • Appropriate oncology applications

Contraindications

  • Absolute: Known hypersensitivity
  • Relative: Organ transplant recipients, active autoimmune disease flare, pregnancy

Special Populations

  • Transplant patients: May interfere with immunosuppression - generally avoid
  • Autoimmune disease: Use with caution; may exacerbate
  • Elderly: May be particularly beneficial for age-related immune decline

Safety Profile

Generally Well-Tolerated

Extensive safety data from international use. Reported effects:

  • Injection site reactions (mild, transient)
  • Fatigue (uncommon)
  • Myalgia (rare)

Serious Adverse Effects

  • Very rare in clinical trials and post-marketing surveillance
  • Allergic reactions (rare)

Long-Term Safety

  • Used chronically in hepatitis treatment with good safety profile
  • No significant long-term toxicity identified

Monitoring Parameters

Baseline Assessment

  • Complete blood count with differential
  • Comprehensive metabolic panel
  • Liver function tests
  • CD4/CD8 ratio (if indicated)
  • Specific infection markers as relevant

Ongoing Monitoring

  • CBC every 4-8 weeks during initial treatment
  • Infection surveillance
  • Subjective response assessment
  • Adverse effect monitoring

Drug Interactions

Limited drug interactions identified:

  • Immunosuppressants: May counteract Ta1 effects; avoid combination
  • Other immunomodulators: Theoretical additive effects
  • Chemotherapy: Often used together; coordinate with oncologist

Compounding Considerations

Quality Requirements

  • Certificate of Analysis with identity and purity verification
  • Sterility and endotoxin testing
  • Lyophilized formulation preferred
  • Proper reconstitution and storage protocols

Storage

  • Lyophilized: Stable at room temperature
  • Reconstituted: Refrigerate at 2-8°C, use within 14 days
  • Protect from light

Regulatory Status

  • NOT FDA-approved in the United States
  • Approved in >35 countries (marketed as Zadaxin)
  • Available through 503A compounding pharmacies in US

Clinical Pearls

  1. Realistic expectations: Immune modulation takes time; effects may take weeks
  2. Documentation: Thorough records of infection frequency and severity
  3. Combination approaches: Works well with other supportive therapies
  4. Oncology coordination: Essential for any cancer-related use
  5. Monitoring matters: Track immune markers when appropriate
  6. Patient education: Explain mechanism and expected timeline

References

  1. Tuthill C, et al. Thymalfasin: biological properties and clinical applications. Int Immunopharmacol. 2000;14(3):129-135.
  2. Garaci E, et al. Thymosin alpha-1 in the treatment of cancer: from basic research to clinical application. Int J Immunopharmacol. 2000;22(12):1067-1076.
  3. Romani L, et al. Thymosin alpha-1 activates dendritic cell tryptophan catabolism and establishes a regulatory environment for balance of inflammation and tolerance. Blood. 2006;108(7):2265-2274.
  4. King R, Tuthill C. Immune Modulation with Thymalfasin (thymosin alpha-1) Treatment: A Review of Treatment of Hepatitis B and Hepatitis C and Other Potential Applications. Expert Opin Biol Ther. 2016;16(sup1):S9-S20.