What Thymosin alpha-1 is
Thymosin alpha-1 — written Tα1, and also known as thymalfasin — is a 28-residue peptide originally isolated from thymic tissue. The thymus is where T-cells mature, and the search for the soluble factors mediating that process is what produced this compound. It is acetylated at the N-terminus, which is both a stability feature and part of its identity: the acetylated form is the active one.
- Thymosin α-128-residue thymic peptide
- TLR2 and TLR9On dendritic cells and monocytes
- MyD88 → NF-κB → Th1 polarisationImmune modulation rather than stimulation
- Immune-response modelsClinical use in several countries
Mechanism as described in published research. Nothing here describes an effect in a person — these compounds are supplied for laboratory research use only.
Immune signalling
The mechanistic literature associates Tα1 with Toll-like receptor signalling, particularly TLR2 and TLR9, on dendritic cells and other antigen-presenting cells. That places it upstream in the immune response rather than acting directly on effector cells — it is studied as a modulator of how an immune response is initiated and shaped, not as something that switches immunity on or off.
That upstream position is why it is described as immunomodulatory rather than immunostimulatory in careful writing, and the distinction matters in study design. Thymalin, a thymic peptide complex rather than a single defined molecule, is studied in the same broad area and is often the comparator.
What the literature covers
Research areas include:
- TLR2 and TLR9 signalling on antigen-presenting cells.
- T-cell maturation and differentiation, following its thymic origin.
- Dendritic cell function and antigen presentation.
- Comparative thymic peptide work against undefined thymic extracts.
Identity and verification
Thymosin alpha-1 has the molecular formula C129H215N33O55 and a molecular weight of 3108.3 g/mol (CAS 62304-98-7). Identifiers matter more here than in most categories: research compounds are sold under trade names, development codes and abbreviations that do not always refer to the same molecule, and a formula is unambiguous where a name is not.
Every lot is tested by an independent laboratory before release. Our certificate library covers the lots currently in stock.
We use two laboratories because purity and identity are different questions. Vanguard Laboratory is ISO/IEC 17025:2017 accredited (A2LA #6377.01.01) and reports chromatographic purity and net quantity with a stated measurement uncertainty. Freedom Diagnostics reports HPLC-UV purity together with LC-MS identity confirmation — the test that catches a substituted compound rather than merely an impure one. A sample can be 99% pure and still be the wrong molecule. How we test →
Handling, reconstitution and storage
Thymosin alpha-1 ships lyophilized — freeze-dried to a solid and sealed under vacuum — which is what makes it stable in transit rather than a solution racing a clock. Reconstitute with bacteriostatic water, added slowly down the inside wall of the vial rather than directly onto the powder, then swirled gently. Do not shake: mechanical shear is one of the few things that reliably degrades a peptide in the lab.
Final concentration is a function of the volume added, not of the compound, so the same vial can be prepared at very different concentrations. The reconstitution calculator works out the volume for a target concentration and the reconstitution guide covers the procedure. Store lyophilized vials at −20 °C (−4 °F) protected from light; refrigerate once in solution, and see the storage and stability guide for how long reconstituted material holds.
Common questions
What is thymosin alpha-1?
A 28-residue peptide originally isolated from thymic tissue, also known as Tα1 or thymalfasin. It is acetylated at the N-terminus, and the acetylated form is the active one.
Is it immunostimulatory?
The literature generally describes it as immunomodulatory rather than immunostimulatory. It acts upstream — on Toll-like receptor signalling in antigen-presenting cells — shaping how a response is initiated rather than switching immunity on.
How does it differ from thymalin?
Thymosin alpha-1 is a single defined 28-residue peptide with a known sequence. Thymalin is a peptide complex extracted from thymic tissue rather than one characterised molecule, which makes it a different kind of research material.
Why is the thymus relevant?
It is where T-cells mature. Thymosin alpha-1 was identified in the search for the soluble factors mediating that process, which is why its literature centres on T-cell and antigen-presenting cell biology.
Where to get it
Buy research-grade Thymosin alpha-1 — independently tested, certificate published, shipped from Miami with cold-chain packaging. Current pricing for every size is on the price list, and we ship worldwide.
Research use only
Everything referenced here is supplied strictly for laboratory research. These compounds are not drugs, foods, cosmetics or medical devices, are not for human or veterinary use, and are not approved for diagnostic or therapeutic application. Mechanisms are described as studied in preclinical and laboratory research; nothing above describes dosing, treatment or clinical outcome.
