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Reviewed by MyPeptideMatch Editorial TeamLast reviewed February 2026Updated February 2026

Thymosin Alpha-1 Dosing Protocol: 5 mg Vial — Immune Modulation Guide

Thymosin Alpha-1 (Ta1) endogenous thymic peptide dosing guide — immune enhancement, antiviral defense, and cancer immunotherapy adjunct protocol.

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Quickstart highlights

Thymosin Alpha-1 (TA1, 28-amino acid acetylated peptide) is the active fraction of thymosin fraction 5, a naturally occurring thymic hormone.

  • Concentration: 1 mg/mL (5 mg vial + 5 mL bacteriostatic water).
  • At 1 mg/mL: 900 µg = 90 units twice weekly (Zadaxin dose).
  • Zhao et al. 2020: Thymosin Alpha-1 reduced COVID-19 ICU mortality — mechanism: T-cell and innate immune activation.
  • Garaci et al. 2012: Thymosin Alpha-1 as cancer immunotherapy adjunct enhances NK cell and T-cell responses.
  • One 5 mg vial provides approximately 5 twice-weekly injection doses at 900 µg.

Dosing table

For educational reference only. Your prescribing provider may adjust doses based on your clinical profile and response.

WeekDose (µg)UnitsFrequencyNotes
1-1290090Twice weekly (Mon and Thu)900 µg — 90 units at 1 mg/mL; FDA-cleared dose (Zadaxin); one 5 mg vial provides ~5 twice-weekly doses (2.5 weeks)
alt1600160Twice weekly1.6 mg — 160 units; higher research dose used in some oncology and HIV protocols

Reconstitution steps

  1. Draw 5 mL bacteriostatic water (two 2.5 mL draws); inject slowly down the vial wall.
  2. Swirl gently until dissolved; do not shake.
  3. Final concentration: 1 mg/mL. At 1 mg/mL: 900 µg = 90 units, 1.6 mg = 160 units.
  4. Label with date; refrigerate at 2–8 °C. Use within 28 days.

Supplies needed

12-week plan

  • 10 vials
  • 24 syringes
  • 50 mL bac water
  • 24 alcohol swabs
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Protocol overview & cycle notes

Enhance T-cell maturation, natural killer cell activity, and innate immune surveillance through twice-weekly Thymosin Alpha-1 subcutaneous injections, restoring thymic immune function in immunocompromised or aging individuals.

Cycle length: 12 weeks on.

Off-cycle: 4 weeks off; reassess immune function markers (NK cell activity, CD4/CD8 ratio) before resuming.

Storage & handling

Lyophilized: store below 25 °C. Reconstituted at 1 mg/mL: refrigerate 2–8 °C; use within 28 days.

Injection & tracking tips

  • Inject subcutaneously (outer thigh, abdomen, or upper arm) on twice-weekly schedule — consistent spacing (3–4 days apart) maintains steady thymulin-like signaling.
  • Thymosin Alpha-1 does not cause injection site pain or systemic side effects at therapeutic doses.
  • If using for acute infection or cancer support, daily dosing at 900 µg for 2 weeks is sometimes used under physician direction.

Tracking

Logging helps you and your provider spot patterns and adjust dose or timing.

  • Measure NK cell activity and CD4+/CD8+ T-cell ratio at baseline and 12 weeks.
  • Track frequency of respiratory infections and illness duration during the protocol period.
  • Log subjective energy and immune robustness (0–10) weekly.
Log your cycle in the calculator →

How this works & references

Thymosin Alpha-1 (TA1, 28-amino acid acetylated peptide) is the active fraction of thymosin fraction 5, a naturally occurring thymic hormone. Processed from prothymosin alpha by thymic epithelial cells, TA1 stimulates: (1) Dendritic cell MHC-II antigen presentation; (2) T helper cell differentiation and IL-2 production; (3) Natural killer cell (NK) cytotoxicity; (4) Type I interferon (IFN-alpha/beta) production; (5) TLR9 signaling potentiation. Thymalfasin (Zadaxin, SciClone) is FDA-approved for hepatitis B (200+ countries), hepatitis C in combination with interferon, and cancer immunotherapy in multiple nations. Zhao et al. (2020, Signal Transduct Target Ther) showed Thymosin Alpha-1 significantly reduced mortality in COVID-19 critical patients.

Sources

  • Source: Garaci E et al. — Thymosin alpha1 in the treatment of cancer. Ann N Y Acad Sci. 2012;1269:145-53
  • Source: Zhao M et al. — Thymosin alpha-1 reduces mortality in COVID-19. Signal Transduct Target Ther. 2020;5:270

Frequently asked questions

Is Thymosin Alpha-1 the same as BPC-157 for immune function?
No — these are entirely different peptides. BPC-157 is a tissue repair peptide with indirect immune effects via gut mucosal integrity. Thymosin Alpha-1 is a thymic hormone that directly activates T-cell maturation, NK cells, and dendritic cell function. They are complementary, not interchangeable.
Can Thymosin Alpha-1 be used during chemotherapy?
Yes — this is one of its primary evidence-based applications. Multiple Asian clinical trials have used TA1 as an adjunct to chemotherapy, showing improved tumor response rates, reduced treatment-related immunosuppression, and better quality of life. The mechanism involves restoring CD4+ T-cell and NK cell function suppressed by chemotherapy agents. Always coordinate with your oncologist.
How long does Thymosin Alpha-1 take to show immune benefits?
NK cell activity and CD4+ T-cell improvements are measurable within 4–6 weeks of twice-weekly dosing. In the hepatitis B trials, HBsAg seroconversion rates improved significantly at 6 months. For general immune enhancement in healthy aging individuals, noticeable reductions in infection frequency typically occur within 8–12 weeks.
Is Thymosin Alpha-1 safe for autoimmune disease patients?
Caution is warranted — TA1 enhances T-cell activity, which could theoretically worsen T-cell-driven autoimmune conditions. However, some published data shows TA1 normalizes immune balance rather than purely stimulating it (reducing Th17, enhancing Treg populations in some models). Patients with active autoimmune disease should use only under specialist guidance.
What is the difference between Thymosin Alpha-1 and Thymosin Beta-4 (TB-500)?
Completely different biological roles: Thymosin Alpha-1 is a thymic immune hormone driving T-cell maturation and innate immunity. Thymosin Beta-4 (from which TB-500 is derived) is an actin-sequestering peptide driving tissue repair, angiogenesis, and wound healing. The shared 'thymosin' name reflects both being originally isolated from thymus gland preparations but implies no functional relationship.

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This content is for informational purposes only and does not constitute medical advice. Consult a licensed healthcare provider before starting any peptide therapy. Dosing and protocols may vary by formulation and prescriber.

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