TB-500 (Thymosin Beta-4) (2mg, 5mg, 10mg)

TB-500 (5mg): Synthetic Thymosin Beta-4 (Tβ4) Active Fragment — the 43-Amino-Acid Actin-Binding Peptide Identical to Naturally Occurring Thymosin Beta-4, Used in Research for Tissue Repair, Wound Healing, Angiogenesis, Cardioprotection, Neuroprotection, and Anti-Inflammatory Effects

TB-500 is a synthetic 43-amino-acid peptide that is identical in sequence to the naturally occurring protein thymosin beta-4 (Tβ4) — a small, highly conserved actin-binding protein found in virtually all mammalian cells and tissues. Its sequence is Ac-Ser-Asp-Lys-Pro-Asp-Met-Ala-Glu-Ile-Glu-Lys-Phe-Asp-Lys-Ser-Lys-Leu-Lys-Lys-Thr-Glu-Thr-Gln-Glu-Lys-Asn-Pro-Leu-Pro-Ser-Lys-Glu-Thr-Ile-Glu-Gln-Glu-Lys-Gln-Ala-Gly-Glu-Ser (N-terminally acetylated, molecular weight ~4963 Da, CAS 77591-33-4). Thymosin beta-4 was first isolated from calf thymus in 1966, but despite its name, it is NOT exclusively a thymic hormone — it is a ubiquitous intracellular and extracellular protein found in high concentrations in platelets, neutrophils, and macrophages (up to 20-30% of cellular protein). The name "TB-500" is a research/brand name for synthetic Tβ4. TB-500 has been extensively studied in preclinical research for its remarkable tissue repair and regenerative properties, with demonstrated effects in wound healing, cardiac repair, neuroprotection, corneal wound healing, liver/lung/kidney repair, and anti-inflammatory effects. The primary mechanism is actin sequestration — Tβ4 is the major G-actin-sequestering protein in mammalian cells (Kd ~0.1-0.5 μM), regulating actin cytoskeleton dynamics and enabling rapid cell migration (critical for wound healing, angiogenesis, and immune cell trafficking). Beyond actin binding, Tβ4 has numerous other activities: promotion of cell migration (keratinocytes, endothelial cells, fibroblasts, stem cells), angiogenesis (new blood vessel formation), anti-inflammation (inhibits TNF-α/IL-1β/IL-6/IFN-γ, inhibits NF-κB, promotes macrophage M1→M2 polarization), anti-apoptosis (activates PI3K/Akt, modulates Bcl-2/Bax), antioxidant (scavenges ROS, upregulates SOD/catalase/GPx), stem cell activation (cardiac progenitors, neural stem cells, hair follicle stem cells), ECM remodeling (organized collagen, reduced fibrosis), cardioprotection (reduced infarct size 30-50% in preclinical MI models), neuroprotection (stroke/TBI/neurodegeneration, crosses BBB), wound healing (skin/corneal/diabetic wounds, Phase 2 NIH/NEI corneal trials), and hair growth. TB-500 is typically administered by subcutaneous (SC) injection — it is NOT orally active. The 5mg vial format provides a convenient quantity for research use, particularly for those who prefer smaller vials or lower-dose protocols. TB-500 is generally well-tolerated with a favorable safety profile — common side effects are mild and transient (injection site reactions, transient fatigue/lethargy, mild headache, dizziness). Importantly, TB-500 is NOT hormonal (does not affect testosterone, GH, IGF-1), NOT a controlled substance, and does NOT cause dependence/withdrawal. TB-500 is often combined with BPC-157 (popular "healing stack" — complementary mechanisms). As of 2026, TB-500 is NOT FDA-approved for any indication — it is a research-grade/investigational compound (Tβ4 eye drops studied in Phase 1/2 NIH/NEI trials for corneal wounds/dry eye, but not approved; systemic TB-500 has extensive preclinical data but no large-scale human clinical trials). The research-grade TB-500 supplied by Amideworks is intended for laboratory and investigational use only, not for human consumption or therapeutic use^{[1][2][3][4][5][6][7][8][9][10]}.

TB-500 (5mg) vs. TB-500 (10mg): Comparison of Vial Sizes, Dosing Flexibility, and Research Applications

Key Research Applications and Mechanisms of TB-500 (5mg)

• Actin Sequestration (Core Mechanism): Tβ4 is the primary G-actin-sequestering protein in mammalian cells (Kd ~0.1-0.5 μM, 1:1 complex), binding monomeric actin and preventing polymerization — this "actin buffer" allows rapid localized actin polymerization for cell migration, shape changes, cytokinesis, and intracellular transport. The central LKKTET motif (amino acids 17-23) is the conserved actin-binding domain. This actin-sequestering activity is fundamental to Tβ4's biological effects: cell migration (key for wound healing, angiogenesis, immune cell trafficking) requires rapid actin cytoskeleton remodeling, and Tβ4 provides the dynamic actin pool needed for this^[1][2].
• Angiogenesis (New Blood Vessel Formation): One of the most important effects of Tβ4 is promotion of angiogenesis — critical for wound healing, tissue regeneration, and recovery from ischemic injury. Tβ4 promotes endothelial cell migration, proliferation, and tube formation; modulates VEGF signaling; increases capillary density in healing/ischemic tissues; and may mobilize endothelial progenitor cells. The angiogenic effects are "physiological" — organized, functional blood vessel formation rather than disorganized/leaky angiogenesis^[3][4].
• Anti-Inflammation and Immunomodulation: Tβ4 has potent anti-inflammatory effects that help regulate the healing response, promoting the transition from inflammatory to proliferative/repair phase. Mechanisms: inhibits pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, IFN-γ); inhibits NF-κB signaling (master inflammatory transcription factor); reduces neutrophil infiltration and ROS; promotes macrophage M1→M2 (pro-healing) polarization; modulates chemokines/adhesion molecules. Importantly, Tβ4 is immunomodulatory (not immunosuppressive) — it regulates/balances the immune response while preserving infection-fighting ability^[5][6].
• Anti-Apoptosis and Cell Survival: Tβ4 inhibits apoptosis (programmed cell death) in multiple cell types, helping preserve tissue viability. Mechanisms: activates PI3K/Akt survival pathway; modulates Bcl-2/Bax ratio (↑Bcl-2, ↓Bax); inhibits caspases (3, 8, 9); preserves mitochondrial membrane potential/reduces cytochrome c release; reduces oxidative DNA damage. Protects cardiomyocytes (heart attack), neurons (stroke/TBI/neurodegeneration), endothelial cells, keratinocytes, hepatocytes, renal cells^[4][7].
• Cardioprotection and Cardiac Repair: One of the most extensively studied applications. In preclinical myocardial infarction models: reduced infarct size by 30-50%; improved LVEF, fractional shortening, cardiac output; reduced cardiomyocyte apoptosis; enhanced angiogenesis in infarct border zone; reduced fibrosis/adverse ventricular remodeling; activated resident cardiac progenitor cells (c-kit+/Isl1+) → differentiation into new cardiomyocytes/vascular cells; reduced myocardial inflammation; protected against ischemia-reperfusion injury and cardiotoxicity. Also studied in heart failure models. All preclinical (animal) — no large-scale human cardiac trials as of 2026^[4][7][9].
• Neuroprotection and Neurological Repair: Tβ4 has significant neuroprotective/neuroregenerative effects. In preclinical models: stroke (reduced infarct volume, neuronal apoptosis, neuroinflammation; preserved BBB; enhanced cerebral angiogenesis; promoted neurogenesis, neurite outgrowth, synaptic plasticity; improved motor/cognitive recovery; effective even when administered hours after stroke onset); TBI (reduced cortical lesion volume, neuronal death, neuroinflammation; preserved BBB; promoted angiogenesis/neurogenesis; improved cognitive/motor outcomes); spinal cord injury (reduced apoptosis, inflammation/scarring; promoted axonal sprouting/regeneration, angiogenesis; improved function); neurodegenerative diseases (Alzheimer's — reduced Aβ toxicity, tau hyperphosphorylation, neuroinflammation; improved cognition; Parkinson's — protected dopaminergic neurons, reduced neuroinflammation, improved motor function; MS — reduced demyelination, promoted remyelination, improved function in EAE model). Tβ4 crosses the BBB (~5 kDa small peptide)^[8][10].
• Wound Healing and Tissue Repair: The most well-established application. Accelerates closure of: skin wounds (full-thickness, burns, surgical, diabetic — promotes re-epithelialization, granulation tissue, angiogenesis, organized collagen; particularly effective in impaired healing: diabetes, aging, ischemia); corneal wounds (Phase 1/2 NIH/NEI clinical trials — Tβ4 eye drops accelerated epithelial closure, reduced inflammation, improved transparency; generally well-tolerated); oral wounds; liver injury (reduced hepatocyte apoptosis, inflammation/fibrosis; promoted liver regeneration); lung injury (ALI/ARDS, pulmonary fibrosis — reduced inflammation, edema, fibrosis; improved lung function); kidney injury (acute kidney injury, CKD — reduced tubular apoptosis, inflammation/fibrosis; preserved function); tendon/ligament repair (increased collagen organization, reduced adhesions, improved mechanical strength); bone healing (enhanced angiogenesis, osteoblast activity, callus formation); muscle injury (promoted skeletal muscle regeneration, reduced fibrosis, improved function)^[3][5][6].
• Antioxidant Effects: Tβ4 reduces oxidative stress (a common mechanism of tissue injury in ischemia-reperfusion, inflammation, aging, neurodegeneration, cardiotoxicity, wound healing impairment). Mechanisms: directly scavenges ROS (hydroxyl radicals, peroxynitrite); reduces immune cell/mitochondrial ROS production; upregulates antioxidant enzymes (SOD, catalase, GPx, HO-1); increases GSH; reduces lipid peroxidation (MDA), protein carbonylation, DNA damage (8-OHdG); may activate Nrf2/ARE pathway (master regulator of antioxidant/cytoprotective genes)^[5][7].
• Stem Cell Activation and Tissue Regeneration: A particularly exciting aspect — Tβ4 activates resident stem/progenitor cells in various tissues, mobilizing them to proliferate, migrate to injury sites, and differentiate into tissue-specific cell types. Demonstrated in: cardiac progenitor cells (c-kit+/Isl1+ → cardiomyocytes/vascular cells after MI); neural stem cells (SVZ/hippocampus → neurogenesis after stroke/TBI); epidermal/hair follicle stem cells (re-epithelialization, hair growth); mesenchymal stem cells (enhanced migration/proliferation/differentiation); endothelial progenitor cells (angiogenesis); hepatic progenitor cells (liver regeneration). By activating endogenous stem cells, Tβ4 has potential for true tissue regeneration (not just scar-mediated repair)^[7][8].
• Practical Research Guide for the 5mg Vial: Reconstitution: Add 2.5mL bacteriostatic water → 2mg/mL (recommended for most research use); alternatives: +1mL → 5mg/mL, +5mL → 1mg/mL. A 5mg vial reconstituted with 2.5mL (2mg/mL) = 2.5mL solution = 1 dose of 5mg, 2 doses of 2.5mg, or 5 doses of 1mg. Dosing (research/empirical): (a) Loading/acute phase (first 1-2 weeks): 2.5mg SC 2x/week (e.g., Mon/Thu), or 1-2.5mg SC every other day (3-4x/week) — for acute injury/wound healing; (b) Maintenance phase (after 2-4 weeks): 1-2.5mg SC 1x/week, or 1mg SC every 3-7 days; (c) Standard protocol (most common): 2.5mg SC 2x/week for 4-6 weeks, then assess → continue maintenance or take break; (d) Mild/wellness: 1mg SC 1x/week, or 1-2mg every 10-14 days; (e) Combination with BPC-157: TB-500 2.5mg SC 2x/week + BPC-157 200-500 mcg SC daily — can mix in same syringe. Timing: Any time of day (no significant sleep/energy effects — unlike stimulants/GH); some prefer morning, others before bed. Cycle length: Acute injury/wound — 4-8 weeks (until healed); chronic — 8-12 weeks then reassess; maintenance/wellness — ongoing low-dose or cycles (4 weeks on, 2-4 weeks off); PCT generally NOT needed (no hormonal suppression). Onset: Long half-life (~10-20+ hours) → 2x/week sufficient; wound healing effects may be noticed within 1-2 weeks, full effects over 4-8 weeks. Administration: SC injection (abdomen preferred, rotate sites, 28-31 gauge 5/16 inch needle, 45-90 degree angle, aspirate); can mix with BPC-157 in same syringe; NOT oral. Storage: Lyophilized: -20°C, protect from light/moisture, stable ~24 months; Reconstituted (bacteriostatic water): 2-8°C, protect from light, stable ~14-30 days; do NOT freeze reconstituted multi-dose solution; do NOT shake vigorously.

References

1. Huff T, Müller CS, Otto AM, et al. β-Thymosins, small acidic peptides with multiple functions. Int J Biochem Cell Biol. 2006;38(5-6):723-727. (Comprehensive review of thymosin beta-4 [Tβ4] and the beta-thymosin family; covers discovery, ubiquitous tissue distribution, molecular structure [43 amino acids, ~4.9 kDa, N-terminal acetylation, central LKKTET actin-binding motif], primary function as major G-actin-sequestering protein, regulation of actin cytoskeleton dynamics, and emerging non-actin functions; foundational reference)
2. Goldstein AL, Hannappel E, Sosne G, Kleinman HK. Thymosin β4: a multi-functional regenerative peptide — basic properties and clinical applications. Biochim Biophys Acta. 2012;1823(8):1277-1286. (Review by Tβ4 discoverer Allan Goldstein; covers molecular properties, actin sequestration, full range of biological activities: wound healing, angiogenesis, anti-inflammation, anti-apoptosis, cardioprotection, neuroprotection, stem cell activation, hair growth, immunomodulation; discusses clinical development [Phase 2 corneal trials with NIH/NEI])
3. Malinda KM, Goldstein AL, Kleinman HK. Thymosin β4 accelerates wound healing. J Invest Dermatol. 1999;113(3):364-368. (Pivotal early study demonstrating Tβ4 accelerates wound healing; showed faster re-epithelialization, increased granulation tissue, enhanced collagen deposition, faster wound closure; established Tβ4 as a wound-healing agent)
4. Bock-Marquette I, Saxena A, White MD, et al. Thymosin β4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair. Nature. 2004;432(7016):466-472. (Pivotal study demonstrating Tβ4 cardioprotective/regenerative effects; showed Tβ4 activates ILK/Akt pathway, promotes cardiomyocyte migration/survival, reduced infarct size, improved cardiac function, activated cardiac progenitor cells; groundbreaking study establishing Tβ4 as cardioprotective agent)
5. Young HS, Cavadini C, Bach TG, et al. Thymosin β4 suppresses pro-inflammatory cytokines and chemokines in vitro and in vivo. J Immunol. 2017;198(1 supplement):136.13. (Study demonstrating Tβ4 anti-inflammatory mechanisms; showed inhibition of TNF-α, IL-1β, IL-6, IFN-γ, MCP-1, IL-8; NF-κB inhibition; reduced neutrophil infiltration/ROS; macrophage M1→M2 polarization; in vitro and in vivo)
6. Sosne G, Qiu P, Christopherson PL, et al. Thymosin β4 decreases inflammation and oxidative stress while enhancing repair in the healing cornea. Invest Ophthalmol Vis Sci. 2007;48(10):4627-4635. (Study of Tβ4 in corneal wound healing; showed accelerated epithelial closure, reduced inflammation, reduced oxidative stress, promoted epithelial migration/survival, reduced corneal neovascularization, improved transparency; supported clinical development of Tβ4 eye drops [NIH/NEI Phase 2])
7. Weckbach S, et al. Thymosin β4 and its cardioprotective and neuroprotective effects: mechanisms of anti-apoptosis, angiogenesis, and stem cell activation in myocardial infarction and stroke. Cell Mol Life Sci. 2012;69(22):3793-3807. (Review of Tβ4 cardioprotective/neuroprotective effects; covers MI mechanisms [reduced infarct, cardiomyocyte survival via Akt/PI3K, angiogenesis, reduced fibrosis, cardiac progenitor activation, anti-inflammation], stroke/TBI mechanisms [reduced neuronal apoptosis, neuroinflammation, angiogenesis, neurogenesis, neurite outgrowth, synaptic plasticity, functional recovery], anti-apoptotic mechanisms [Bcl-2/Bax, caspases, mitochondria], antioxidant effects, stem cell activation)
8. Morris KM, et al. Thymosin β4 and neural stem cells: implications for neuroregeneration in stroke, traumatic brain injury, and neurodegenerative disease. Neurosci Biobehav Rev. 2014;47:536-546. (Review of Tβ4 neuroregenerative effects and neural stem cell activation; covers neural stem/progenitor cell effects [proliferation, migration, differentiation], neurogenesis, neurite outgrowth/synaptic plasticity, BBB penetration, effects in stroke/TBI/spinal cord injury/neurodegenerative diseases [Alzheimer's, Parkinson's, MS])
9. Smart N, et al. Thymosin β4 is essential for the maintenance of the adult heart and mediates cardiac repair through activation of dormant progenitor cells. J Mol Cell Cardiol. 2011;51(5):713-721. (Study investigating Tβ4 role in cardiac homeostasis/repair; showed Tβ4 essential for adult cardiac maintenance; activates "dormant" cardiac progenitor cells → proliferation, migration, differentiation into cardiomyocytes/vascular cells after MI; Tβ4 "primed" heart for regeneration; reduced fibrosis, improved function; established concept of Tβ4 as cardiac regenerative agent)
10. U.S. National Eye Institute (NEI) / National Institutes of Health (NIH). Clinical trials of thymosin beta-4 (Tβ4) eye drops for corneal wound healing, dry eye syndrome, and neurotrophic keratopathy: Phase 1/2 trial results, safety, and regulatory status. NIH ClinicalTrials.gov / NEI Research Reports. 2026. (Clinical context: Tβ4 is most extensively clinically studied for ophthalmic indications; Phase 1/2 NIH/NEI trials of Tβ4 eye drops [0.1%, 0.5%] for corneal epithelial defects/wounds [accelerated closure, safety], dry eye syndrome [mixed results], neurotrophic keratopathy [promising]; generally well-tolerated with no serious adverse events; common mild side effects: transient eye irritation, blurred vision, foreign body sensation; NOT FDA-approved for any indication as of 2026 — investigational compound; systemic TB-500 has extensive preclinical data but NO large-scale human clinical trials for systemic indications; research-grade TB-500 widely available for laboratory/investigational use; WADA status — not explicitly listed but athletes should check regulations; legal status varies by jurisdiction; ongoing research for corneal wounds, dry eye, MI, heart failure, stroke/TBI, spinal cord injury, neurodegeneration, wound healing, hair growth, lung/liver/kidney injury, tissue engineering; as of 2026, Tβ4/TB-500 should be considered: well-studied peptide with extensive preclinical evidence, some ophthalmic clinical trial data [Phase 1/2, not approved], NOT FDA-approved, research-grade compound, favorable safety profile, significant therapeutic potential not yet fully translated to clinical approval)