Thymosin Alpha-1.
Thymosin alpha-1 (TA-1) is a 28-amino acid peptide derived from prothymosin alpha in the thymus, approved in over 35 countries as Zadaxin for hepatitis B and C — the most clinically validated peptide in the research market.
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- Key Signals
- Immunity · Antiviral · Immunomodulation
- Origin
- Synthetic (prothymosin alpha fragment)
- Investigator
- Goldstein et al. (George Washington), 1977
- Class
- N-acetylated thymic immunomodulatory 28-mer
- Status (UAE)
- Research compound (off-label)
The Thymus's Signal, Now Approved in 35 Countries
Goldstein's group isolates thymosin alpha-1 from calf thymus in 1977, identifying it as the immunologically active fraction of thymosin fraction 5.
Zadaxin (synthetic TA-1) gains approval in over 35 countries for hepatitis B and C — the most extensive regulatory footprint of any research-market peptide.
Research expands to cancer immunotherapy and COVID-19, where TA-1 is used as an immune adjuvant in Chinese clinical protocols.
Twenty-eight residues, the thymus in a vial.
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
C₁₂₉H₂₁₅N₃₃O₅₅ · MW 3108.4 Da
Thymosin alpha-1 is derived from prothymosin alpha in thymic epithelial cells — a 28-residue immunomodulatory sequence driving T-cell maturation, dendritic cell activation, and Toll-like receptor signalling.
Genuine drug approvals, not in the US or UAE.
Approved as Zadaxin in 35+ countries; no FDA, EMA, or MOHAP approval for any indication.
- T-cell maturation confirmed
- NK cell activation shown
- Dendritic cell stimulation
- TLR9 agonism established
- Apoptosis induction (tumour models)
- HBV: viral load reduction (Zadaxin)
- HCV: SVR improvement (Zadaxin)
- Cancer adjuvant (Asian RCTs)
- COVID-19 adjuvant (China protocols)
- Long COVID immune restoration
- Autoimmune condition modulation
- Immunosenescence (anti-aging)
- Post-chemotherapy immune recovery
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Approved in 35+ Countries, Not in the US or UAE
In the UAE, research-grade peptides occupy a defined regulatory category distinct from licensed medicines. Compounds sold under this classification — including those offered by Dubai Peptides — are intended exclusively for qualified research applications, not for human administration.
Thymosin alpha-1 (Zadaxin) holds marketing approval in over 35 countries for chronic hepatitis B and C, and as a cancer immunotherapy adjuvant in several Asian and Eastern European jurisdictions. Neither the FDA, EMA, nor MOHAP has approved it. A separate off-label market for the research-grade compound exists in the UAE, distinct from Zadaxin's regulated distribution and outside the research-use classification this platform follows.
Goldstein's group isolates thymosin alpha-1 from calf thymus, identifying it as the immunologically active fraction of thymosin fraction 5.
Zadaxin (synthetic TA-1) receives marketing approval in Italy for hepatitis B, marking the first regulatory approval of a thymic peptide drug.
Chinese regulatory authorities approve Zadaxin for hepatitis C and cancer immunotherapy — extending the compound's approved indications to over 35 countries.