TB-500 / TB4 — Peptide Protocol Wiki reference
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TB-500 (Thymosin Beta-4): Tissue Repair Guide | Peptide Protocol Wiki Skip to main content 🧬 Peptide Protocol Wiki Peptides Side Effects New Learn Directory Tools Blog News About ⌘K ⌘K 🌱 New to Peptides? Start the 7-step beginner guide Peptides Side Effects New Directory Learn Tools Blog News About TB500 📋 Overview 🧬 Molecule 🔄 Similar ⚠️ Side Effects 💉 Dosing 🔬 Research 🚨 Risks 👥 Community 📊 Community Data Home Peptides TB500 Healing & Tissue Repair Immune Support phase2 TB500 Also known as: Thymosin Beta-4, TB-500, Timbetasin, Thymosin Beta 4, Tβ4 Compare with 3 peptide s Research compiled by Peptide Protocol Wiki 📅 Updated February 8, 2026 Citations Verified TL;DR TB500 is a synthetic version of Thymosin Beta-4 (Tβ4), a naturally occurring 43-amino acid peptide present in virtually all human and animal cells. It functions primarily through G-actin sequestration, promoting cell migration, angiogenesis, and tissue repair.
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Findings (69) · awaiting review (32)
safety · pending
TB-500 (Thymosin Beta-4): Tissue Repair Guide | Peptide Protocol Wiki Skip to main content 🧬 Peptide Protocol Wiki Peptides Side Effects New Learn Directory Tools Blog News About ⌘K ⌘K 🌱 New to Peptides?
dosing · pending
Start the 7-step beginner guide Peptides Side Effects New Directory Learn Tools Blog News About TB500 📋 Overview 🧬 Molecule 🔄 Similar ⚠️ Side Effects 💉 Dosing 🔬 Research 🚨 Risks 👥 Community 📊 Community Data Home Peptides TB500 Healing & Tissue Repair Immune Support phase2 TB500 Also known as: Thymosin Beta-4, TB-500, Timbetasin, Thymosin Beta 4, Tβ4 Compare with 3 peptide s Research compiled by Peptide Protocol Wiki 📅 Updated February 8, 2026 Citations Verified TL;DR TB500 is a synthetic version of Thymosin Beta-4 (Tβ4), a naturally occurring 43-amino acid peptide present in virtually all human and animal cells.
mechanism · pending
It functions primarily through G-actin sequestration, promoting cell migration, angiogenesis, and tissue repair.
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Browse all healing peptides → Table of Contents 📌 TL;DR • Promotes cell migration and tissue repair by sequestering G-actin and modulating cytoskeletal dynamics • Investigated in phase II clinical trials for dermal wound healing and corneal injuries • Demonstrated cardioprotective effects after myocardial infarction in p
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tion # Actin Sequestration and Cytoskeletal Regulation # The most well-characterized function of Thymosin Beta-4 is its role as the principal actin-sequestering protein in eukaryotic cells.
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reclinical models • Modulates inflammatory responses by inhibiting NF-kB signaling and reducing pro-inflammatory cytokines • Reduces fibrosis and scar formation through decreased myofibroblast activity Community-Reported Side Effects Anecdotal ?
dosing · pending
📋 Protocol Quick-Reference Tissue repair, wound healing, and injury recovery 💉 Dosing Amount 2-2.5 mg per injection (loading); 750 mcg-2 mg (maintenance) Frequency 2-3 times per week (loading phase); 1-2 times per week (maintenance) Duration Loading: 4-6 weeks; Maintenance: 4-8 weeks; total 8-12 weeks Step-wise Titration (12 weeks) 💊 Administration Route SC Schedule 2-3 times per week (loading phase); 1-2 times per week (maintenance) Timing No specific time of day required; consistency preferred ✓ Rotate injection sites 📅 Cycle Duration Loading: 4-6 weeks; Maintenance: 4-8 weeks; total 8-12 weeks Repeatable Yes Loading phase followed by maintenance Preparation & Storage Diluent: Bacteriostatic water Storage: Store lyophilized (unreconstituted) vials at -20C for long-term storage or 2-8C (refrigerator) for short-term.
contraindication · pending
fects blood cell migration CMP with liver enzymes When: Baseline Why: Liver and kidney function baseline CRP or ESR When: Baseline Why: Baseline inflammation markers to track healing response Ferritin When: Baseline Why: Iron status if recovering from surgery or injury CBC When: 4 weeks Why: Monitor blood cell parameters CRP When: 4 weeks Why: Track inflammatory marker improvement with tissue healing 💡 Key Considerations → Contraindication: Avoid with active cancer or recent cancer history (promotes angiogenesis and cell migration); not for use in pregnancy Subscribe to unlock this content Get weekly peptide research summaries, new study alerts, and protocol updates — free.
outcome · pending
Restore access No thanks, continue reading Related Reading Peptide BPC-157 body protection compound peptide Peptide GHK-Cu copper peptide for tissue repair Article The Complete Guide to Peptide Stacks: Popular Combinations Explained How TB500 works at the cellular level Overview of TB500 benefits and applications Scientific Details Molecular Formula C212H350N56O78S Molecular Weight 4963.44 Da CAS Number 77591-33-4 Sequence Ac-SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES What is TB500?
mechanism · pending
The peptide is encoded by the TMSB4X gene in humans and is expressed in virtually every cell type, with particularly high concentrations found in platelets, macrophages, and polymorphonuclear leukocytes.
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This actin-buffering capacity is essential for the regulation of the cytoskeleton, which in turn governs cell shape, motility, and division.
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Within cells, Thymosin Beta-4 maintains a large reservoir of unpolymerized actin that can be rapidly mobilized when the cell needs to migrate, divide, or change shape in response to extracellular signals.
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When released from damaged cells or secreted by platelets at sites of injury, it acts as a paracrine signaling molecule that promotes wound healing, angiogenesis, and anti-inflammatory responses.
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Mechanism of Ac
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When a cell receives a migration or proliferation signal, signaling pathways trigger the release of G-actin from the Tβ4 complex, allowing profilin to facilitate actin polymerization at the leading edge of the cell.
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Cell Migration and Angiogenesis # TB500 promotes the migration of multiple cell types critical to tissue repair, including endothelial cells, keratinocytes, and cardiac progenitor cells.
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In wound healing models, topical or systemic administration of Thymosin Beta-4 increased keratinocyte migration 2- to 3-fold over controls in Boyden chamber assays (Goldstein AL et al., Expert Opin Biol Ther 2012; PMID 22074294) 1 .
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The pro-migratory effect is mediated through activation of integrin-linked kinase (ILK), which in turn activates the Akt/protein kinase B survival pathway 1 .
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The peptide promotes endothelial cell differentiation, tubule formation, and sprouting angiogenesis in both in vitro and in vivo models 1 .
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Anti-Inflammatory and Anti-Fibrotic Activity # Thymosin Beta-4 exerts anti-inflammatory effects through multiple mechanisms.
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It inhibits TNF-alpha-stimulated NF-kB binding activity through its interaction with PINCH-1 and ILK signaling partners, independently of its actin-sequestering function.
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In corneal injury models, Thymosin Beta-4 treatment reduced polymorphonuclear leukocyte infiltration and decreased mRNA transcript levels of interleukin-1 beta, MIP-1alpha, MIP-2, and MCP-1 by several fold compared to controls.
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In dermal wound models, Thymosin Beta-4 reduces the number of myofibroblasts in healing wounds, which results in decreased scar formation.
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This anti-fibrotic effect has been observed in cardiac tissue as well, where Tβ4 treatment reduced fibrosis following myocardial infarction in animal models.
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Cardioprotective Mechanisms # Thymosin Beta-4 has demonstrated remarkable cardioprotective properties in preclinical models.
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In mouse models of coronary artery ligation, systemic administration of Tβ4 resulted in upregulation of ILK and Akt phosphorylation in the heart, enhanced early myocyte survival, and significantly improved cardiac function.
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This regenerative capacity represents a novel mechanism for cardiac repair that is distinct from conventional stem cell therapies.
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In the foundational 1999 study by Malinda and colleagues (PMID 10469335 [animal model]) 2 , topical or intraperitoneal administration of Tβ4 increased re-epithelialization by 42% over saline controls at 4 days and by 61% at 7 days post-wounding in a rat full-thickness wound model 2 .
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Treated wounds also showed increased collagen deposition, enhanced angiogenesis, and accelerated wound contraction 2 .
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The peptide demonstrated efficacy across multiple wound types, including diabetic wounds, aged-animal wounds, and steroid-impaired healing models 3 .
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Studies by Sosne and colleagues demonstrated that topical Tβ4 accelerated corneal re-epithelialization, decreased inflammation, and reduced polymorphonuclear leukocyte infiltration after alkali injury in mouse models.
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In a randomized, double-blind phase II trial (NCT01387347), RGN-259 demonstrated a 35.1% reduction in ocular discomfort and a 59.1% reduction in total corneal fluorescein staining compared to vehicle control.
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Following coronary artery ligation in mice, systemic Tβ4 administration improved left ventricular function, reduced infarct size, and decreased cardiac fibrosi
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These effects were mediated through ILK-Akt survival signaling and mobilization of epicardial progenitor cells 1 .
safety · pending
Clinical translation of these findings has been slower, with early-phase human studies focusing on safety and tolerability.
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A first-in-human Phase I trial in healthy Chinese volunteers reported no dose-limiting toxicities or serious adverse events (Wang X et al., 2021; PMID 34346165) 5 .
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Earlier Allan-led work reported tolerability at IV doses up to 1260 mg with no dose-limiting toxicities.
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Pharmacokinetics # Following intravenous administration in healthy volunteers, Thymosin Beta-4 exhibited dose-proportional pharmacokinetics across the tested range of 42 to 1260 mg (Wang X et al., 2021; PMID 34346165) 5 .
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The half-life increased with increasing dose, suggesting non-linear elimination kinetics at higher concentrations 5 .
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Tβ4 is naturally present in serum at concentrations of approximately 12-18 ng/mL in healthy individuals, and endogenous levels increase at sites of injury due to platelet degranulation and cellular release.
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