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Thymosin beta 4 and thymosin alpha 1: two different peptides

Thymosin beta 4 and thymosin alpha 1 share a name and a thymic history but are different peptides. Thymosin beta 4 has 43 residues and binds G-actin. Thymosin alpha 1 has 28 residues and is N-acetylated. TB-500 is the name used for synthetic thymosin beta 4.

Written by the Peptency editorial teamLast reviewed 5 studies checked in PubMed on 5 October 2026

Research-use information. This page summarises published literature and regulator records. It is not guidance for use, not medical advice, and not a statement that any material is suitable for use in people or animals.

What is thymosin beta 4?

Thymosin beta 4 is a ubiquitous 43-residue, 5 kDa peptide, the most abundant beta-thymosin in mammalian tissue, regarded as the main G-actin sequestering peptide. Reviews describe it as a mediator of cell migration, proliferation and differentiation. A rat wound-model study measured re-epithelialisation and wound contraction.[4],[1],[5]

What is thymosin alpha 1?

Thymosin alpha 1 is a 28-residue peptide first described and characterised from calf thymus in 1977. Reviews describe effects on T cells, dendritic cells and cytokine production, and work in tumour models.[2],[3]

Which compounds in the catalog belong to this group?

Thymosin beta 4 (43 residues)TB-500

C212H350N56O78S, 4963 g/mol

N-acetylated 28-residue peptideThymosin α1

C129H215N33O55, 3108.3 g/mol

Research materials: TB-500, Thymosin α1.

Which studies are cited on this page?

  1. [1] Goldstein AL, Hannappel E, Sosne G, Kleinman HK. Thymosin β4: a multi-functional regenerative peptide. Basic properties and clinical applications. Expert Opin Biol Ther. 2012;12:37-51.

    Review of thymosin beta 4 properties: actin binding, cell migration and reported tissue-repair roles.

    ReviewPMID 22074294DOI 10.1517/14712598.2012.634793

  2. [2] Li J, Liu CH, Wang FS. Thymosin alpha 1: biological activities, applications and genetic engineering production. Peptides. 2010;31:2151-8.

    Review of thymosin alpha 1 effects on T cells, dendritic cells and cytokines, and of recombinant production methods.

    ReviewPMID 20699109DOI 10.1016/j.peptides.2010.07.026

  3. [3] Garaci E, Favalli C, Pica F, Sinibaldi Vallebona P, Palamara AT, Matteucci C, et al.. Thymosin alpha 1: from bench to bedside. Ann N Y Acad Sci. 2007;1112:225-34.

    Review of preclinical tumour models and the development path of thymosin alpha 1.

    ReviewPMID 17600290DOI 10.1196/annals.1415.044

  4. [4] Philp D, Huff T, Gho YS, Hannappel E, Kleinman HK. The actin binding site on thymosin beta4 promotes angiogenesis. FASEB J. 2003;17:2103-5.

    Mapped the actin-binding region of thymosin beta 4 and tested its angiogenic activity in endothelial-cell and tissue assays.

    In vitro and animal studyPMID 14500546DOI 10.1096/fj.03-0121fje

  5. [5] Malinda KM, Sidhu GS, Mani H, Banaudha K, Maheshwari RK, Goldstein AL, et al.. Thymosin beta4 accelerates wound healing. J Invest Dermatol. 1999;113:364-8.

    Measured wound re-epithelialisation and contraction in a rat full-thickness wound model.

    Animal studyPMID 10469335DOI 10.1046/j.1523-1747.1999.00708.x

Data dates: citations read from PubMed 2026-10-05.