Biology:Thymosin α1

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Short description: Protein-coding gene in the species Homo sapiens

A representation of the 3D structure of the protein myoglobin showing turquoise α-helices.
Generic protein structure example
Thymosin α1
Identifiers
CAS Number
PubChem CID
Chemical and physical data
FormulaC129H215N33O55
Molar mass3108.315 g·mol−1
3D model (JSmol)

Thymosin α1 is a peptide fragment derived from prothymosin alpha, a protein that in humans is encoded by the PTMA gene.[1]

It was the first of the peptides from Thymosin Fraction 5 to be completely sequenced and synthesized. Unlike β thymosins, to which it is genetically and chemically unrelated, thymosin α1 is produced as a 28-amino acid fragment having the sequence Ac-SDAAVDTSSEITTKDLKEKKEVEEEAEN, which is made from cleavage of a longer, 113-amino acid precursor, prothymosin α.[2]

Function

Thymosin α1 is an agonist for toll-like receptor 2 and toll-like receptor 9 on both myeloid and dendritic antigen-presenting cells, thereby stimulating the adaptive immune response.[3]

Thymosin α1 is believed to be a major component of Thymosin Fraction 5 responsible for the activity of that preparation in restoring immune function in animals lacking thymus glands. It has been found to enhance cell-mediated immunity in humans as well as experimental animals.[4]

Therapeutic application

Thymosin α1 is approved in some countries for the treatment of Hepatitis B and C, and it is also used to boost the immune response in the treatment of other diseases.[5][6] The synthetic version of Thymosin α1 is known as Thymalfasin and is sold under the brand name Zadaxin.[7]

Thymosin α1 is usually administered by subcutaneous injection.[3]

Clinical studies

Clinical trials suggest thymosin α1 may be useful in cystic fibrosis, septic shock,[8] acute respiratory distress syndrome, peritonitis, pancreatitis,[9] acute cytomegalovirus infection, TB, severe acute respiratory syndrome, and lung infections in critically ill patients.,[6][10] and for chronic hepatitis B.[11][12][13]

For hospitalized COVID-19 patients, a 2023 review concluded thymosin α1 was not effective in reducing mortality or length of hospitalization.[14] A subsequent 2023 review contradicted this, showing a reduction in mortality but not length of stay.[15]

It has been studied for possible use in treating cancer (e.g. with chemotherapy).[16]

See also

References

  1. ↑ "The human prothymosin alpha gene family contains several processed pseudogenes lacking deleterious lesions". Genomics 13 (2): 319–31. Jul 1992. doi:10.1016/0888-7543(92)90248-Q. PMID 1612591. https://zenodo.org/record/1258589. 
  2. ↑ Garaci E (September 2007). "Thymosin alpha1: a historical overview". Ann. N. Y. Acad. Sci. 1112: 14–20. doi:10.1196/annals.1415.039. PMID 17567941. 
  3. ↑ 3.0 3.1 "Thymosin alpha 1: A comprehensive review of the literature". World Journal of Virology 9 (5): 67–78. 2020. doi:10.5501/wjv.v9.i5.67. PMID 33362999. 
  4. ↑ "Thymosin activity in patients with cellular immunodeficiency". N. Engl. J. Med. 292 (2): 70–4. January 1975. doi:10.1056/NEJM197501092920204. PMID 1078552. 
  5. ↑ "Thymosin alpha 1: from bench to bedside". Ann. N. Y. Acad. Sci. 1112 (1): 225–34. September 2007. doi:10.1196/annals.1415.044. PMID 17600290. Bibcode: 2007NYASA1112..225G. 
  6. ↑ 6.0 6.1 "From lab to bedside: emerging clinical applications of thymosin alpha 1". Expert Opin Biol Ther 9 (5): 593–608. May 2009. doi:10.1517/14712590902911412. PMID 19392576. 
  7. ↑ "Therapeutic applications of thymosin peptides: A patent landscape 2018-present". Expert Opinion on Therapeutic Patents 33 (12): 865–873. 2023. doi:10.1080/13543776.2023.2298833. PMID 38131310. 
  8. ↑ "Efficacy of thymosin α1 for sepsis: A systematic review and meta-analysis of randomized controlled trials". Frontiers in Cellular and Infection Microbiology 15. 2025. doi:10.3389/fcimb.2025.1673959. PMID 40969554. 
  9. ↑ "Thymosin alpha 1 alleviates inflammation and prevents infection in patients with severe acute pancreatitis through immune regulation: A systematic review and meta-analysis". Frontiers in Immunology 16. 2025. doi:10.3389/fimmu.2025.1571456. PMID 40599771. 
  10. ↑ "Thymosin Alpha 1 Plus Routine Treatment for the Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis". Journal of the College of Physicians and Surgeons Pakistan 34 (12): 1497–1507. 2024. doi:10.29271/jcpsp.2024.12.1497. PMID 39648386. 
  11. ↑ "Thymosin alpha-1 treatment in chronic hepatitis B". Expert Opinion on Biological Therapy 15: 129–132. 2015. doi:10.1517/14712598.2015.1007948. PMID 25640173. 
  12. ↑ "Comprehensive Review of the Safety and Efficacy of Thymosin Alpha 1 in Human Clinical Trials". Alternative Therapies in Health and Medicine 30 (1): 6–12. 2024. PMID 38308608. 
  13. ↑ "Aging and Thymosin Alpha-1". International Journal of Molecular Sciences 26 (23). 2025. doi:10.3390/ijms262311470. PMID 41373628. 
  14. ↑ "Thymosin alpha1 use in adult COVID-19 patients: A systematic review and meta-analysis on clinical outcomes". International Immunopharmacology 114. 2023. doi:10.1016/j.intimp.2022.109584. PMID 36527881. 
  15. ↑ "The efficacy of thymosin alpha-1 therapy in moderate to critical COVID-19 patients: A systematic review, meta-analysis, and meta-regression". Inflammopharmacology 31 (6): 3317–3325. 2023. doi:10.1007/s10787-023-01354-2. PMID 37845598. 
  16. ↑ "Thymosin alpha 1 in the treatment of cancer: from basic research to clinical application". Int J Immunopharmacol 22 (12): 1067–76. 2000. doi:10.1016/s0192-0561(00)00075-8. PMID 11137613. 

Further reading