Also known as: Thymosin Beta-4 Fragment · TB-4 Fragment 17-23 · Ac-LKKTETQ · TB500 fragment
TB4-Frag is a synthetic 7-amino acid fragment of thymosin beta-4 (residues 17–23) that retains the core anti-inflammatory and tissue repair activity of the full TB-500 peptide. It offers a more cost-effective and stable alternative with comparable healing, actin-binding, and anti-inflammatory properties.
TB4-Frag (Ac-LKKTETQ) corresponds to the actin-binding domain of thymosin beta-4, the region responsible for most of its biological activity. Research shows it retains the ability to promote wound healing, reduce inflammation, and modulate actin polymerisation — the core mechanisms behind TB-500 — in a smaller, more stable, and more economical molecule.
TB4-Frag sequesters G-actin monomers through its LKKTET motif, modulating actin dynamics in migrating cells and promoting wound closure. It also downregulates NF-κB-mediated inflammatory signalling, reduces IL-6 and TNF-α production, and promotes VEGF-driven neovascularisation in ischaemic tissue.
TB4-Frag is used as a TB-500 alternative or complement. Less human data available than for full-length TB-500, but preclinical evidence supports comparable bioactivity in key wound healing and anti-inflammatory assays. Source quality important — the short peptide is easier to synthesise but also easier to adulterate; use reputable research suppliers. Well tolerated based on available data.
Injury-focused protocols use higher loading doses for 4–6 weeks. Long-term tissue maintenance uses lower doses over 8–12 weeks with periodic breaks. Can be stacked with BPC-157 throughout the cycle for synergistic healing effects.
Research dosing mirrors TB-500 protocols: 2–5 mg twice weekly subcutaneously. Considered well-tolerated based on available preclinical data. The shorter chain offers improved stability and shelf life over full-length TB-500. Often stacked with BPC-157 for synergistic tissue repair.
Ask anything about TB4-Frag — mechanisms, dosing protocols, interactions, or research comparisons.
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