Thymosin Beta-4
A 43 amino acid peptide involved in cell migration, wound healing, and tissue repair through effects on actin polymerisation. Thymosin beta-4 and its fragment TB-500 are widely discussed research peptides for tissue repair applications. They are classified as research compounds in major jurisdictions.
Technical Context
Tβ4 (SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES, 43 aa) is the most abundant actin-sequestering peptide in mammalian cells. Preclinical wound healing data: Tβ4 promotes corneal wound healing (accelerating re-epithelialisation in multiple animal models), cardiac repair after myocardial infarction (activating epicardial progenitor cells in mouse models), and dermal wound healing (accelerating closure and reducing scarring in rodent models). TB-500 is typically described as a synthetic fragment of Tβ4, commonly the 17 amino acid active region. RegeneRx Biopharmaceuticals developed RGN-259 (Tβ4 eye drops) for neurotrophic keratopathy and dry eye — Phase III trials were conducted but the programme did not achieve approval. The broader tissue repair claims for Tβ4/TB-500 in the research peptide space are based primarily on preclinical models without adequate human clinical trial validation.