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Thymosin Beta-4
Tβ4, TB4 (full-length 43-amino-acid peptide; distinct from the shorter synthetic TB-500 fragment often sold as interchangeable)
Thymosin beta-4 (Tβ4) is an endogenous 43-amino-acid, ~5 kDa peptide and the principal G-actin-sequestering molecule in mammalian cells, buffering the monomeric actin pool that governs cytoskeletal assembly and cell motility. Beyond actin binding it behaves as a pleiotropic 'moonlighting' peptide: preclinical studies link it to endothelial-cell migration and angiogenesis, laminin upregulation and matrix remodelling, anti-inflammatory and anti-apoptotic signalling, and — via its actin-binding region and the derived tetrapeptide Ac-SDKP — to cardiac and neural repair, partly through integrin-linked kinase and Akt survival pathways. It is chemically distinct from TB-500, a shorter synthetic fragment frequently marketed as if equivalent.
Tβ4 has a deep endogenous-biology and rodent evidence base spanning wound healing, corneal repair, angiogenesis and post-injury cardiac and neural protection. Human evidence is limited and preliminary: proprietary formulations (RegeneRx's dermal RGN-137, injectable RGN-352 for cardiac/CNS repair, and the ophthalmic RGN-259 for dry eye and corneal wounds) reached only early-phase trials; the systemic RGN-352 program was discontinued and no formulation holds full marketing approval. Gray-market 'TB-500' is a different, shorter fragment, not the studied full-length peptide.
- Studied in wound- and corneal-injury healing models
- Angiogenesis and endothelial-cell migration research
- Post-injury cardiac and neural tissue-repair models
- Anti-inflammatory and cell-survival signalling research
Educational overview only — no dosing instructions in the public hub.
Long-term human safety is not established; only early-phase trial data exist for defined pharmaceutical formulations, not for gray-market material. As a pro-angiogenic, pro-migratory peptide there is a theoretical concern about promoting unwanted vascular growth or tumour biology, unproven in humans. The dominant practical risk is product identity and quality: full-length Tβ4 is frequently mislabelled as, or substituted with, the shorter TB-500 fragment, and unregulated vials carry the usual purity, endotoxin and sterility uncertainties, used without medical supervision.
Material sold as Tβ4 or 'TB-500' outside pharmaceutical channels is unregulated and often of unverified identity. A third-party Certificate of Analysis with identity, purity (HPLC), quantification and mass spectrometry is the minimum verification, and should confirm the full 43-amino-acid sequence rather than a fragment. Sterility and endotoxin are usually undocumented. The content here describes research findings, not a quality-assured medicine.
Research-use-only in most jurisdictions and not an approved drug for human use. The World Anti-Doping Agency prohibits Tβ4 and related actin-binding/growth-factor peptides (including TB-500) in sport at all times. It is not authorised as a dietary supplement or food ingredient.
Frequently asked questions
- What is Thymosin Beta-4 used for?
- Studied in wound- and corneal-injury healing models. Angiogenesis and endothelial-cell migration research. Post-injury cardiac and neural tissue-repair models. Anti-inflammatory and cell-survival signalling research. Tβ4 has a deep endogenous-biology and rodent evidence base spanning wound healing, corneal repair, angiogenesis and post-injury cardiac and neural protection. Human evidence is limited and preliminary: proprietary formulations (RegeneRx's dermal RGN-137, injectable RGN-352 for cardiac/CNS repair, and the ophthalmic RGN-259 for dry eye and corneal wounds) reached only early-phase trials; the systemic RGN-352 program was discontinued and no formulation holds full marketing approval. Gray-market 'TB-500' is a different, shorter fragment, not the studied full-length peptide.
- Is Thymosin Beta-4 legal in Europe?
- Research-use-only in most jurisdictions and not an approved drug for human use. The World Anti-Doping Agency prohibits Tβ4 and related actin-binding/growth-factor peptides (including TB-500) in sport at all times. It is not authorised as a dietary supplement or food ingredient.
- What are the risks and side effects of Thymosin Beta-4?
- Long-term human safety is not established; only early-phase trial data exist for defined pharmaceutical formulations, not for gray-market material. As a pro-angiogenic, pro-migratory peptide there is a theoretical concern about promoting unwanted vascular growth or tumour biology, unproven in humans. The dominant practical risk is product identity and quality: full-length Tβ4 is frequently mislabelled as, or substituted with, the shorter TB-500 fragment, and unregulated vials carry the usual purity, endotoxin and sterility uncertainties, used without medical supervision.
- How is the quality of Thymosin Beta-4 assessed?
- Material sold as Tβ4 or 'TB-500' outside pharmaceutical channels is unregulated and often of unverified identity. A third-party Certificate of Analysis with identity, purity (HPLC), quantification and mass spectrometry is the minimum verification, and should confirm the full 43-amino-acid sequence rather than a fragment. Sterility and endotoxin are usually undocumented. The content here describes research findings, not a quality-assured medicine.