Thymosin Alpha-1 / TA-1
The gold standard immune modulator — FDA-approved equivalent (Zadaxin) with strong RCT data in viral infections, cancer, and immune deficiency.
Research facts
| Half-life | ~2h |
|---|---|
| Route | SubQ |
| Typical dose | 1.6 mg twice weekly |
| Frequency | Twice weekly SubQ |
| Solvent | Bacteriostatic water |
| pH | 6.8–7.4 |
| Stability | 30 days at +4°C |
Mechanism of action
Thymosin Alpha-1 (Tα1) is a 28-amino acid peptide naturally produced by the thymus gland. It is a potent immunomodulator that enhances both innate and adaptive immune function through multiple mechanisms: induction of T-cell differentiation and maturation (particularly Th1 polarisation), upregulation of MHC-I expression on tumour cells (improving immune visibility), activation of NK cells and dendritic cells, and augmentation of cytokine production (IFN-γ, IL-2, TNF-α). It is sold as Zadaxin (SciClone Pharmaceuticals) and is approved in 35+ countries for hepatitis B, hepatitis C, and as an adjuvant in cancer immunotherapy. Placebo-controlled trials in COVID-19 showed reduced mortality in severe cases. RCT data in sepsis shows improved survival. This evidence base earns it B-tier.
Documented effects (research-model)
- T-cell maturation and Th1 polarisation for cellular immunity
- NK cell and dendritic cell activation
- Hepatitis B and C viral clearance enhancement (approved)
- Improved outcomes in sepsis (RCT data)
- COVID-19 severity reduction (RCT)
- Cancer immunotherapy adjuvant (35+ country approval)
Research protocols
| Protocol | Dose | Frequency | Cycle | Vial |
|---|---|---|---|---|
| Standard | 1.6 mg twice weekly SubQ | Twice weekly | 6–12 months for chronic viral; 4–8 weeks for seasonal | 1.6mg per vial |
Research context only. Not medical advice. Consult a qualified healthcare professional before any protocol decision.
Synergies
Myths & misconceptions
Evidence gaps
- Most trials are in immunocompromised or diseased populations — evidence in healthy individuals for "immune enhancement" is sparse.
- Optimal dose for different applications (viral, cancer, prophylactic) not uniformly established across the literature.
- UK/EU regulatory status as a research compound — not licensed in UK for these indications.
Safety notes
Excellent safety profile from 35+ country approval history. No significant adverse events in clinical trials. Well-tolerated over long treatment periods. Generally considered the safest immune peptide in this library.
Biomarkers to monitor
Primary-source citations
- PMID 23840720 — Thymalfasin (thymosin alpha-1) treatment of chronic hepatitis B (Aliment Pharmacol Ther. 2013)
- PMID 33836948 — Thymosin alpha-1 reduces mortality of severe COVID-19 patients (Clin Infect Dis. 2021)
Frequently asked
What is Thymosin Alpha-1 / TA-1?
Thymosin Alpha-1 / TA-1 (Thymalfasin — Thymic Immunomodulatory Peptide) is a research compound classified in our library as Tier B — Some human data + strong preclinical evidence.. The gold standard immune modulator — FDA-approved equivalent (Zadaxin) with strong RCT data in viral infections, cancer, and immune deficiency.
What is the evidence tier for Thymosin Alpha-1 / TA-1?
We classify Thymosin Alpha-1 / TA-1 as Tier B: Some human data + strong preclinical evidence. See our full peptide evidence tiers explainer for how we assign S/A/B/C/D.
What is the research dose of Thymosin Alpha-1 / TA-1?
For Thymosin Alpha-1 / TA-1, typical research dose is 1.6 mg twice weekly, route is SubQ, half-life is ~2h. Protocols vary by research goal — see the protocols section on this page for standard and advanced dosing schedules. Research use only, not medical advice.
Is Thymosin Alpha-1 / TA-1 safe?
Excellent safety profile from 35+ country approval history. No significant adverse events in clinical trials. Research context only — no compound on this site is approved for human therapeutic use unless explicitly noted.