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Thymosin Alpha-1
5 mg lyophilized powder in a sealed glass vial.
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- 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
- CAS number
- 62304-98-7
- Molecular weight
- 3108.3 g/mol
- Counter-ion
- Stated on the certificate of analysis
- Contents
- Thymosin Alpha-1 · 5 mg per vial
- Form
- Lyophilized powder, sealed under inert gas
- Storage
- 2–8 °C sealed, protected from light
- Documentation
- Certificate of Analysis per batch, linked via QR
- Delivery
- Ships from our warehouse in Poland within 1–3 working days, tracked, no customs within the EU. Typically 3–5 working days; shipping €9.00, free from €150.
What Thymosin Alpha-1 is
Thymosin alpha-1 (thymalfasin) is a peptide of 28 amino acids with an acetylated N-terminus. It was first isolated in 1977 from thymosin fraction 5, an extract of calf thymus, and is produced in the body by cleavage of the larger protein prothymosin alpha. The peptide is acidic, highly water-soluble and has no fixed three-dimensional structure in solution. A synthetic form, thymalfasin, has been manufactured since the 1980s and is marketed as the medicine Zadaxin in a number of countries. It is supplied here as a lyophilized (freeze-dried) powder for laboratory research.
What the research examines
Immune signalling. Cell-culture and mouse studies examined how thymosin alpha-1 acts on dendritic cells and T cells. Work by Romani and colleagues reported activation of Toll-like receptor signalling (TLR2 and TLR9) in dendritic cells, increased interleukin-12 output and induction of indoleamine 2,3-dioxygenase, and characterised the peptide as a regulator of both inflammatory and tolerogenic responses in models of fungal infection.
Chronic viral hepatitis. The largest clinical literature concerns hepatitis B and C. A randomised controlled trial in 98 people with chronic hepatitis B compared 26 or 52 weeks of thymalfasin with no treatment, measuring clearance of HBV DNA and HBeAg over 18 months, and reported the proportion with complete virological response in each of the three groups. Later meta-analyses examined thymalfasin combined with interferon.
Sepsis trials. Two randomised trials in China examined thymosin alpha-1 in sepsis. A single-blind trial of 361 participants (2013) reported a lower 28-day mortality that did not reach statistical significance. The double-blind phase 3 TESTS trial (2025, 1,106 participants, 22 centres) measured 28-day all-cause mortality and reported no significant difference from placebo on that endpoint or on any secondary outcome.
Oncology and vaccination. Thymosin alpha-1 has been examined alongside chemotherapy and as a vaccine adjuvant. A randomised study of 488 people with metastatic melanoma compared dacarbazine with or without thymosin alpha-1 and interferon alfa, reporting tumour response rates in each arm and a survival difference that was not statistically significant. Smaller trials measured antibody responses to influenza and hepatitis B vaccines in older adults.
Randomised human trials of thymosin alpha-1 exist in hepatitis B, sepsis and melanoma, with mixed outcomes. Thymalfasin is an approved medicine in more than 30 countries, marketed as Zadaxin since its Chinese approval in 1996, mainly for chronic hepatitis B; it is not approved in the United States or European Union. The research-grade material sold here is not a medicine, and this page makes no claims about effects in humans.
Selected literature
- Goldstein AL, et al. Proceedings of the National Academy of Sciences, 1977, primary isolation and sequencing report. doi:10.1073/pnas.74.2.725
- Romani L, et al. Annals of the New York Academy of Sciences, 2007, review of mechanism (dendritic cells, Toll-like receptor signalling). doi:10.1196/annals.1415.002
- Chien RN, et al. Hepatology, 1998, randomised controlled trial, 98 participants. doi:10.1002/hep.510270527
- Maio M, et al. Journal of Clinical Oncology, 2010, randomised study, 488 participants. doi:10.1200/JCO.2009.25.5208
- Wu J, et al. BMJ, 2025, phase 3 trial, 1,106 participants. doi:10.1136/bmj-2024-082583
Every reference is listed with its DOI in the research library.
Handling in the laboratory
Store sealed at 2–8 °C for routine use or frozen for long-term storage, protected from light and moisture. Let the vial reach room temperature before opening. See Storage and handling of lyophilized research peptides.
New to research peptides?
What is a research peptide?
A short chain of amino acids produced synthetically for laboratory investigation. Research peptides are sold as chemical reagents to study biological mechanisms; they are not medicines, foods or supplements and are not for human use.
What does "lyophilized" mean?
Freeze-dried. The peptide is supplied as a dry powder, which keeps it stable in storage. It is dissolved in the laboratory before use in an experiment.
How do I verify a batch?
Scan the QR on the vial, or open "Verify a batch" and enter the batch number. The report opens on the independent laboratory's own website, we cannot edit it.
What does the purity figure mean?
The share of the vial's peptide content that is the intended sequence, measured by HPLC. Identity is confirmed separately by mass spectrometry, so both "what" and "how pure" are tested.
How should it be stored?
Sealed vials at 2–8 °C, protected from light. Our storage guide covers handling of opened vials.