Thymosin Beta-4

Thymosin Beta-4 (Tβ4) is a naturally occurring 43-amino acid protein found in virtually all mammalian cells. It is the most abundant actin-binding protein in the body, responsible for sequestering G-actin monomers and regulating the assembly of actin filaments — the cytoskeletal structures critical for cell migration, division, and wound healing. Tβ4 also activates integrin-linked kinase (ILK), promoting cell survival, migration, and angiogenesis. TB-500 is a synthetic fragment of Tβ4 (specifically the actin-binding domain, amino acids 17-23) designed to replicate its key healing activities. The full-length protein additionally exerts effects through mechanisms not captured by the fragment, particularly in cardiac tissue repair and neurological applications. Some practitioners prefer full-length Tβ4 for broader systemic effects.

Thymosin Beta-4 has been studied for over three decades. The RegeneRx Biopharmaceuticals Phase 2 trials demonstrated corneal wound healing in neurotrophic keratopathy, establishing human safety and tissue-repair efficacy. Cardiac applications are among the most compelling: animal studies show Tβ4 treatment after myocardial infarction significantly reduces scar tissue and promotes cardiomyocyte survival, regeneration, and angiogenesis. The full-length protein has a broader receptor interaction profile than TB-500 — the fragment was developed precisely because it is easier and cheaper to synthesise while retaining the key actin-binding activity for musculoskeletal applications. For users specifically interested in cardiac tissue support or broader systemic regeneration, the full-length protein may be preferred over the fragment.

4–8 weeks