Quick answer
Thymosin alpha-1 (Tα1) is a 28-amino-acid, N-acetylated peptide first isolated from a calf thymus extract in 1977 and studied in immunology research on T-cell and dendritic-cell function in cell and animal models — research findings, not claims about human use. It is a different peptide from TB-500, which relates to thymosin beta-4. Pepspan will supply a 10 mg vial at €94.90, shipped from Spain, with every lot independently tested; coming soon — join the waitlist with Notify me. Updated 30 September 2026.
What Thymosin Alpha-1 Is
Thymosin alpha-1 (Tα1) is a 28-amino-acid peptide, acetylated at its N-terminus, first isolated from thymosin fraction 5 — a calf thymus extract — in 1977. It corresponds to the N-terminal region of prothymosin alpha, a protein expressed in many tissues.
The sequence is 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, with a molecular formula of C129H215N33O55 and a molecular weight of approximately 3,108.3 g/mol. It is supplied as a white lyophilized powder — a reference material for laboratory research, not a drug, food, cosmetic or dietary supplement.
What Research Looks At
Tα1 is studied as an immunomodulatory peptide. In cell and animal models it has been reported to influence T-cell maturation and differentiation, the activation of dendritic cells through Toll-like receptor (TLR) signalling, and the balance of cytokines associated with Th1-type responses.
Published research areas include infection and host-response models, vaccine-response (adjuvant) studies, immune ageing (immunosenescence) and tumour immunology. These findings describe research settings in cell and animal models; they are not claims about human use or about any specific product.
Thymosin Alpha-1 vs TB-500 (Thymosin Beta-4)
Despite the similar name, thymosin alpha-1 and TB-500 are different peptides. TB-500 is a peptide related to thymosin beta-4, a separate 43-amino-acid protein that contains the LKKTET actin-binding motif at residues 17-22. Thymosin alpha-1, by contrast, is a 28-amino-acid peptide derived from prothymosin alpha.
The two share part of their name only because both were first described in thymus tissue extracts. They differ in sequence, size and the research areas that cite them: Tα1 is studied mainly in immunology (T-cell and dendritic-cell function), while thymosin beta-4 and the TB-500 fragment are studied mainly for actin binding and tissue-repair models. See the TB-500 research guide for the separate compound.
The distinction matters when reading the wider literature: a search for "thymosin" alone returns papers on both families. Researchers looking for immunology-focused material should look specifically for thymosin alpha-1 or Tα1, while those interested in actin binding or tissue-repair models should look for thymosin beta-4 or TB-500.
| Thymosin Alpha-1 | TB-500 (Thymosin Beta-4 fragment) | |
|---|---|---|
| Derived from | N-terminal region of prothymosin alpha; isolated from thymosin fraction 5 (calf thymus extract), 1977 | Related to thymosin beta-4, a 43-amino-acid actin-binding protein |
| Sequence feature | 28 residues, N-terminal acetylation | Contains the LKKTET actin-binding motif (residues 17-22 of thymosin beta-4) |
| Molecular formula | C129H215N33O55 | C212H350N56O78S (thymosin beta-4) |
| Main research area | Immunology — T-cell and dendritic-cell function | Actin binding and tissue-repair models |
| At Pepspan | 10 mg vial, €94.90 — coming soon, waitlist | 5 mg vial, €49.90 — in stock |
What to Check When Sourcing Thymosin Alpha-1 in the EU
Before ordering a Tα1 vial from an EU shop, a few things are worth checking on the product page itself:
- A per-lot report from an independent laboratory. A report tied to the specific production lot on the vial, issued by an independent laboratory, with a way to verify it — not a generic specification sheet reused across batches.
- A working verification link. Ideally a link that opens the result directly on the laboratory's own site, rather than only a PDF or image hosted by the seller.
- Content per vial against the label claim. A purity percentage and a measured content in milligrams per vial are two different figures; check which one, or both, the report gives.
- Shipping inside the EU and the seller's returns policy. An EU-based shipping point usually avoids customs processing; check the return window for unopened products.
At Pepspan, the first lot of Thymosin Alpha-1 will be analysed on arrival by an independent laboratory, with the report and a verification link published on its public lot page; every later lot is analysed and published the same way. Orders ship tracked from Spain: after dispatch, delivery typically takes 1-3 business days within Spain, 1-2 to Portugal, 3-5 to Germany and Italy, up to 5 to the Netherlands, and usually 2-5 business days across the rest of the EU. EU shipping is free on orders from €50 (otherwise €6), and unopened products can be returned within 14 days — see the shipping policy and refund policy.
Availability at Pepspan
Thymosin Alpha-1 is not in stock yet at Pepspan. The product page lists a 10 mg lyophilized vial at €94.90, with a purity specification of ≥98% by HPLC; leave your email with the Notify me button to be told as soon as the first lot is in stock. Its independent report will be published on the lot page.
Once available, the lot report will also appear on the purity reports page alongside Pepspan's other published results, and it can be checked as described in the COA verification guide.
Frequently asked questions
What is Thymosin Alpha-1?
Thymosin alpha-1 (Tα1) is a 28-amino-acid, N-terminally acetylated peptide first isolated from a thymus extract (thymosin fraction 5) in 1977. It corresponds to the N-terminal region of prothymosin alpha and is studied in immunology research, mainly in cell and animal models.
Is Thymosin Alpha-1 the same as TB-500?
No. TB-500 is related to thymosin beta-4, a separate 43-amino-acid protein studied for actin binding and tissue-repair models. Thymosin alpha-1 is a 28-amino-acid peptide derived from prothymosin alpha and studied mainly in immunology; the two share part of their name only because both were first described in thymus extracts.
What research areas study Thymosin Alpha-1?
Published research on thymosin alpha-1 covers T-cell maturation and differentiation, dendritic-cell activation through Toll-like receptor signalling, cytokine balance, infection and host-response models, vaccine-response (adjuvant) studies, immune ageing and tumour immunology — all in cell and animal models.
Where was Thymosin Alpha-1 first discovered?
It was first isolated from thymosin fraction 5, a calf thymus extract, by researchers including Allan Goldstein in 1977, and later shown to correspond to the N-terminal region of prothymosin alpha.
How should Thymosin Alpha-1 be stored?
As a lyophilized powder, it is stored at -20°C for long-term storage or at 2-8°C for short periods, protected from light and moisture.
When will Thymosin Alpha-1 be available at Pepspan?
Thymosin Alpha-1 is coming soon. Use the Notify me button on the product page to receive an email as soon as the first lot is in stock; its independent lab report will be published on the lot page.
Where can I buy Thymosin Alpha-1 in Europe?
Pepspan will supply Thymosin Alpha-1 as a 10 mg lyophilized vial at €94.90, shipped tracked from Spain; EU shipping is free on orders from €50 (otherwise €6). It is not in stock yet: join the waitlist with the Notify me button. Rules on buying and handling research peptides differ by country; check your local regulations. Research use only.
Research Use Only: all products mentioned are intended exclusively for laboratory research and are not for human or veterinary use. Information about other suppliers reflects their public websites as checked on the date stated and may change.