TB-500 (Thymosin Beta-4 Fragment 17–23)

TB-500 is a synthetic heptapeptide (LKKTETQ) fragment of Thymosin Beta-4 that binds G-actin to support cytoskeletal repair, angiogenesis, and tissue regeneration. Used for soft-tissue healing and recovery.

- Recover from injury or physical strain

- Accelerate tissue repair

Mechanism of Action

How this peptide works in the body

Actin Sequestration and Cell Migration

The LKKTETQ motif is the primary actin-binding region of Tβ4. This fragment binds G-actin monomers, preventing their premature polymerization and allowing cells to dynamically reorganize their cytoskeleton. This actin remodeling enables cell motility, which is critical for the migration of fibroblasts, keratinocytes, and endothelial cells into the site of injury to initiate repair.

Promotion of Angiogenesis

TB-500 stimulates new blood vessel formation by enhancing the migration and alignment of endothelial cells. It indirectly activates the vascular endothelial growth factor (VEGF) pathway and increases nitric oxide (NO) availability via upregulation of endothelial nitric oxide synthase (eNOS). This improves perfusion of healing tissues and supports sustained regeneration.

Inhibition of Fibrotic Tissue Development

Although not directly antifibrotic, this fragment may reduce inappropriate scar tissue formation by limiting the expression of α-smooth muscle actin (α-SMA) and inhibiting myofibroblast persistence in healing tissue. This results in more elastic and functional tissue regeneration.

Stimulation of Regenerative Signaling Cascades

Activates downstream effectors of PI3K/Akt and FAK (focal adhesion kinase) signaling, both of which are critical for cellular survival, adhesion, and proliferation. These pathways are essential for coordinating the rapid repair of muscle and tendon fibers after mechanical injury.

Support of Stem/Progenitor Cell Recruitment

Emerging data suggest this fragment may attract resident progenitor cells, including satellite cells in skeletal muscle and tenocytes in tendons, accelerating localized tissue turnover and repair.