Thymosin Alpha-1: Structure, Research Overview and Specifications
Thymosin Alpha-1 (Tα1, thymalfasin) is a 28-amino-acid peptide originally isolated from the thymus gland. It is one of the most studied immunomodulatory peptides, researched for its effects on T-cell maturation, dendritic cell signalling and immune response. This page summarises its chemistry, the published research and the specifications of the material we supply.
For in vitro research use only. Not for human or animal use. Nothing on this page is medical advice.
What is Thymosin Alpha-1?
Thymosin Alpha-1 is a naturally occurring peptide produced from a larger precursor protein, prothymosin alpha. It was first purified from thymus tissue in the 1970s and has since been produced synthetically under the name thymalfasin.
In the research literature it is studied mainly as an immune modulator: a compound that influences how immune cells mature, communicate and respond, rather than one that targets a single pathogen or tissue.
Chemical data
| Name | Thymosin Alpha-1 (Tα1) |
|---|---|
| Other names | Thymalfasin, Zadaxin (brand name in some countries) |
| Sequence | 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-OH (Ac-SDAAVDTSSEITTKDLKEKKEVVEEAEN) |
| Length | 28 amino acids (N-terminal acetylated) |
| Molecular formula | C129H215N33O55 |
| Molecular weight | ≈ 3108.3 g/mol |
| CAS number | 62304-98-7 |
| Form supplied | Lyophilised (freeze-dried) powder |
Origin: a peptide from the thymus
The thymus is the organ where T cells mature. In the 1960s and 1970s, researchers led by Allan Goldstein studied a thymus extract called thymosin fraction 5 and identified several active peptides within it. Thymosin Alpha-1 was the first to be isolated and sequenced, in 1977.
Despite the similar name, Thymosin Alpha-1 is unrelated in structure and function to thymosin beta-4, the protein that TB-500 is based on. The “thymosin” name reflects where they were first found, not a shared mechanism.
Proposed mechanisms studied
- Toll-like receptorsResearch reports that Tα1 acts on Toll-like receptors (including TLR2 and TLR9) on dendritic cells, which help start immune responses.
- T-cell maturationTα1 has been studied for its role in promoting the maturation and differentiation of T cells.
- Th1 responseStudies describe a shift towards Th1-type immune signalling, associated with responses to viruses and intracellular pathogens.
- Cytokine signallingResearch has linked Tα1 to changes in cytokines such as interleukin-2 and interferon-gamma.
What the published research shows
Dendritic cells and immune signalling
Laboratory work has shown that Tα1 can activate dendritic cells through Toll-like receptor pathways, influencing how the immune system recognises and responds to fungal and viral challenges in experimental models.
Clinical research in chronic hepatitis
Thymalfasin has been studied in clinical trials in chronic hepatitis B and C, both alone and alongside other treatments. Results have varied between studies and populations.
Vaccine response research
Tα1 has been investigated as an adjuvant to improve vaccine responses, particularly in older or immunocompromised groups in clinical research settings.
Severe infection research
Observational and clinical studies have examined Tα1 in severe infections, including sepsis and COVID-19, focusing on lymphocyte counts and T-cell exhaustion. Findings are mixed and the subject of ongoing research.
Limitations of the evidence
- Many clinical studies are small, single-country or observational, which limits how firmly conclusions can be drawn.
- Results have been inconsistent across conditions and trial designs.
- Much of the mechanistic evidence comes from cell and animal models.
- The full receptor mechanism is still being investigated.
Regulatory status
Thymalfasin is approved as a medicine in a number of countries, but it is not approved in the UK or the US. The Thymosin Alpha-1 we supply is a research-grade compound, not a licensed medicinal product, and is sold strictly for in vitro laboratory research. It is not intended for human or animal use.
Storage and handling in the lab
- Store lyophilised powder at −20 °C, protected from light and moisture, for long-term stability.
- Allow the vial to reach room temperature before opening to reduce condensation.
- Once reconstituted for experiments, keep refrigerated (2–8 °C) and avoid repeated freeze–thaw cycles.
- Avoid vigorous shaking of solutions, which can damage longer peptides.
Quality
Every batch of Thymosin Alpha-1 we supply is independently tested for purity by Janoshik using HPLC before it is released for sale. Read more on our Quality & Testing page.
Related research compounds
Frequently asked questions
Is Thymosin Alpha-1 the same as thymalfasin?
Yes. Thymalfasin is the name for synthetic Thymosin Alpha-1, which has the same 28-amino-acid sequence as the naturally occurring peptide.
What is the difference between Thymosin Alpha-1 and TB-500?
They are unrelated peptides. Thymosin Alpha-1 is studied for immune modulation, while TB-500 is based on thymosin beta-4, an actin-binding protein studied in cell migration and tissue repair. Both were first found in thymus extracts, which is why they share the name.
How does Thymosin Alpha-1 work?
Research suggests it acts on Toll-like receptors on dendritic cells and promotes T-cell maturation and Th1-type immune signalling.
Is Thymosin Alpha-1 approved in the UK?
No. Thymalfasin is approved in some countries but not in the UK or the US. Our product is a research-grade compound supplied strictly for laboratory research.
How should Thymosin Alpha-1 be stored?
Lyophilised Thymosin Alpha-1 should be stored at −20 °C, protected from light and moisture. Reconstituted solutions should be kept refrigerated and not repeatedly frozen and thawed.
References
- Goldstein AL, et al. Thymosin alpha1: isolation and sequence analysis of an immunologically active thymic polypeptide. Proceedings of the National Academy of Sciences USA. 1977;74(2):725–729.
- Romani L, et al. Thymosin alpha 1 activates dendritic cells for antifungal Th1 resistance through toll-like receptor signaling. Blood. 2004;103(11):4232–4239.
- Goldstein AL, Goldstein AL. From lab to bedside: emerging clinical applications of thymosin alpha 1. Expert Opinion on Biological Therapy. 2009;9(5):593–608.
- Liu Y, et al. Thymosin alpha 1 reduces the mortality of severe coronavirus disease 2019 by restoration of lymphocytopenia and reversion of exhausted T cells. Clinical Infectious Diseases. 2020;71(16):2150–2157.
This page is for scientific information only. Sterling Peptides Ltd supplies Thymosin Alpha-1 strictly for in vitro laboratory research. Not for human or animal use, and not for diagnostic or therapeutic purposes. Questions: [email protected]