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).
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.
Quick Start Guide
Reconstitute with 1 mL sterile or bacteriostatic water per 1.6 mg vial.
Inject 1.6 mg subcutaneously twice weekly (standard Zadaxin protocol) or 900 mcg twice weekly (research protocols).
Morning injection preferred for circadian alignment with immune activation.
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 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.
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.
Verify what you have
Information on this page applies to pharmaceutical-grade peptides. Purity & identity of research-grade products vary. Certipep provides independent ESI-TOF-MS & HPLC analysis with a signed analytical report.
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