Thymosin Beta-4
Tβ4 · TMSB4X · Full-length thymosin beta-4
Last reviewed:
- CAS
- 77591-33-4
- MW
- 4963 Da
- Research focus
- regenerationskin woundtendon ligament
A 43-amino-acid actin-sequestering peptide expressed in nearly all human cells. Distinct from the shorter TB-500 fragment; investigated in cardiac repair, corneal healing, and dermal regeneration.
Mechanism of action
Tβ4 is the principal G-actin-sequestering protein in mammalian cells, maintaining an intracellular pool of monomeric actin available for filament assembly. Extracellular effects observed in research models include upregulation of laminin-5, MMP-2/-9, integrin-linked kinase, and angiopoietin-2, leading to cell migration, angiogenesis, and dampening of NF-κB-driven inflammation.
Research history
Isolated from bovine thymus by Allan Goldstein in 1981. Full-length recombinant Tβ4 (RGN-259 ophthalmic, RGN-352 systemic) reached early-phase clinical trials for dry-eye disease, neurotrophic keratitis, and acute myocardial infarction; results have been mixed, with the corneal indication producing the strongest signals.
Summarised studies
Tβ4 mobilises epicardial progenitors after MI
Smart N. et al., Nature · 2007
Adult mice given Tβ4 after experimental myocardial infarction showed reactivation of dormant epicardial progenitors and improved post-infarct neovascularisation.
Tβ4 in neurotrophic keratitis
Sosne G. et al., Cornea · 2020
Topical RGN-259 (recombinant Tβ4) accelerated corneal re-epithelialisation in patients with stage 1–2 neurotrophic keratitis, with favourable safety.
Safety profile
Phase I/II human exposure to recombinant Tβ4 (in ophthalmic and intravenous formulations) has not raised major safety concerns. Theoretical risks of promoting tumour growth via increased angiogenesis are recognised in the literature but unproven. Research-grade synthetic Tβ4 has not been subjected to the same safety characterisation as the GMP recombinant product.
UK regulatory status
Thymosin beta-4 is not an approved medicine in the UK. Some recombinant Tβ4 products have completed early-phase clinical trials abroad but none have UK marketing authorisation. WADA lists Tβ4 under S2.
Frequently asked questions
How does full-length Tβ4 differ from TB-500?
What is the elimination half-life of Tβ4 in humans?
Is recombinant Tβ4 approved anywhere?
Where to source Thymosin Beta-4 for laboratory research
The following UK-based suppliers stock research-grade, lyophilised peptides for in-vitro and pre-clinical work. Purity and provenance vary; always request a Certificate of Analysis (CoA) and confirm cold-chain storage on arrival. None of the products linked below are approved for human use.
- PeptideAuthority.co.uk
UK-based research peptide supplier with batch certificates of analysis and >99% purity testing.
- PeptideBarn.co.uk
Wide catalogue of research-grade lyophilised peptides shipped from the UK, including bulk vials.
Appears in research stacks
Cited in research summaries
Related peptides
TB-500
A synthetic peptide commonly described as a fragment of thymosin beta-4 incorporating the actin-binding 'LKKTETQ' motif. Studied for soft-tissue repair, wound healing, and cardiac tissue regeneration in animal models.
BPC-157
A 15-amino-acid pentadecapeptide derived from a protective protein found in human gastric juice. The most-studied healing research peptide, with extensive pre-clinical work on tendon, ligament, gut, and vascular repair.
TB-500 Fragment (AC-SDKP)
A naturally occurring N-terminal tetrapeptide cleaved from thymosin beta-4. Distinct anti-fibrotic and angiogenic profile in research models, particularly in cardiac and renal fibrosis.
GHK-Cu
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Epitalon
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