Thymosin Alpha-1
Thymic Immune ModulatorAlso known as: Thymalfasin · Zadaxin · Tα1
An FDA-approved 28-amino-acid thymic peptide that enhances innate & adaptive immunity. Used clinically for hepatitis B/C, cancer adjuvant therapy, & immune deficiency.
Typical Dose
900 mcg–1.6 mg twice weekly
Route
Subcutaneous injection
Cycle
6–12 weeks for acute immune support; longer cycles for chronic immune deficiency
Half-life
~2 hours
Storage
Lyophilized: 2–8°C. Reconstituted: refrigerate, use within 24–48 hours (preservative-free) or 30 days (BAC water).
Insights on this page are consolidated from peer-reviewed literature and aggregated research data. They do not constitute medical advice. Consult a qualified healthcare professional before use.
Overview
Thymosin Alpha-1 (Tα1) is the biologically active N-terminal fragment of Prothymosin-Alpha, naturally produced by the thymus gland. It has been approved in over 35 countries under the brand name Zadaxin for treatment of viral hepatitis, malignancy, & immune reconstitution. The FDA has granted Orphan Drug designation for several indications.
Its mechanism involves upregulation of Toll-like receptors (TLR2, TLR9) on dendritic cells, enhancement of NK cell activity, induction of T-helper cell differentiation (Th1 polarization), & augmentation of cytotoxic T-lymphocyte activity. Unlike immunosuppressants, Tα1 restores immune competence without driving autoimmunity.
In research & wellness use, Tα1 is used during & after acute illness, cancer treatment, or chronic viral infection. It is one of the few peptides with a substantial human clinical evidence base at therapeutic doses.
Research Indications
Immune modulation & reconstitution
Most EffectiveRestores NK cell, T-cell, & dendritic cell function in immune-compromised states. Clinical approval in multiple countries.
Viral hepatitis B & C
Most EffectiveZadaxin approved for hepatitis B & C. Reduces viral load & enhances immune clearance in combination with antiviral therapy.
Cancer adjuvant therapy
EffectiveReduces chemotherapy-related immunosuppression & may enhance immune recognition of tumor cells. Used alongside standard oncology protocols.
Acute infection support
EffectiveReduces severity & duration of viral & bacterial infections in immune-competent hosts. Used in COVID-19 severe illness protocols in multiple countries.
Research References
Thymosin alpha1 activates complement receptor-mediated phagocytosis in human monocyte-derived macrophages
Journal of Leukocyte Biology · 2010
Demonstrates Tα1's direct activation of innate immune cells via TLR2/TLR9 pathways.
Thymosin alpha 1 treatment in patients with COVID-19 pneumonia
Frontiers in Pharmacology · 2020
Retrospective analysis showing reduced mortality & faster discharge in severe COVID-19 patients treated with Tα1.
Research Protocols
General immune support
6–12 weeksDose
900 mcg
Frequency
Twice weekly SubQ
Route
SubQ abdomen
Clinical protocol (Zadaxin)
6 months for chronic hepatitisDose
1.6 mg
Frequency
Twice weekly
Route
SubQ
Acute illness support
2–4 weeksDose
1.6 mg
Frequency
Daily for 5–7 days, then 2x/week
Route
SubQ
Peptide Interactions
Side Effects & Safety
Common
- Injection site redness or mild swelling
- Mild fatigue (first 1–2 doses)
Uncommon
- Headache
- Low-grade fever (immune activation; typically resolves within 24h)
When to Stop
- Signs of systemic allergic reaction
- Active autoimmune disease exacerbation (theoretical concern given immune activation)
How to Reconstitute
Wipe stopper with alcohol.
Draw 1 mL bacteriostatic water into syringe.
Inject slowly down inner vial wall.
Swirl gently. Solution should be clear.
Refrigerate. Use within 30 days.
Dosing math: 1 mL BAC water per 1.6 mg vial = 1600 mcg/mL. For 900 mcg dose: 0.56 mL. For 1.6 mg: 1.0 mL.
Quality Indicators
Good — use as normal
- Crystal clear, colorless solution
Acceptable
- Very slight cloudiness that clears immediately
Discard immediately
- Persistent cloudiness
- Particulate
- Discoloration
What to Expect
Week 1–2
NK cell & dendritic cell upregulation begins within days. Some users report increased energy & reduced susceptibility to opportunistic infections.
Week 3–6
T-cell counts improving in baseline-deficient states. Viral load reduction (if applicable) begins to be measurable.
Week 7–12
Cumulative immune reconstitution. In healthy users, subjective improvements in infection resistance & recovery speed.
Community Insights
Self-reported. Reflects user experience, not clinical outcomes.
Verify what you have
Information on this page applies to pharmaceutical-grade peptides. Purity & identity of research-grade products vary. Certipep provides independent ESI-QTOF-MS & HPLC analysis with a signed analytical report.
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