All information below describes the compound's chemical identity, laboratory handling, and the published research literature. It describes molecular targets and results in laboratory and animal models only — not effects in humans — and is not evidence of any human benefit.
What Is TB-500 (Thymosin Beta-4)?
TB-500 is a synthetic peptide corresponding to Thymosin Beta-4 (Tβ4), a naturally occurring 43-amino-acid peptide first isolated from thymic tissue in the 1960s and subsequently identified as one of the most abundant intracellular peptides across nucleated mammalian cells. Tβ4 is a member of the beta-thymosin family of small, highly conserved actin-binding peptides. TB-500 is the corresponding synthetic construct used as a laboratory reference compound.
It is supplied as a reference compound for in vitro and animal research use only. The sections below summarize its chemical identity, laboratory handling, the molecular targets and model systems examined in the published literature, and the primary references — without describing outcomes, efficacy, or effects in humans.
Research Targets & Pathways
Published preclinical literature has examined Thymosin Beta-4 in relation to several molecular systems. These are pathway associations reported in laboratory and animal models; refer to the cited studies for methods and findings.
- G-actin sequestration — examined in relation to high-affinity binding of globular (monomeric) actin and the regulation of actin-filament polymerization dynamics.
- Integrin-linked kinase (ILK) / Akt signaling — examined in cardiac progenitor and endothelial cell assay systems.
- NF-κB pathway — examined in corneal epithelial cell models of cytokine-induced signaling.
- TGF-β pathway — examined in relation to collagen-deposition markers across tissue models.
- Endothelial migration / angiogenesis signaling — examined in endothelial cell migration and tube-formation assays.
- Inflammatory cytokine signaling (TNF-α, IL-1β) — examined in corneal cell model systems.
Model Systems Studied
Thymosin Beta-4 and TB-500 have been used as test compounds across a range of published preclinical model systems, spanning rodent, porcine, and in vitro cell assays. Refer to the cited literature for study designs, endpoints, and findings.
- Dermal — full-thickness and excisional dermal wound models in rodents; murine skin wound models (including microneedle-delivery systems).
- Corneal — corneal epithelial cell migration and wound-closure models, in vitro and in vivo.
- Cardiac — murine myocardial infarction models, living myocardial slice systems, and epicardial progenitor-cell mobilization studies.
- Vascular — ischemic limb revascularization and porcine chronic-ischemia models.
- Nervous system — 5×FAD Alzheimer's disease mouse model (Thymosin β4-derived peptides) and neurite-outgrowth assays.
- In vitro — actin-polymerization assays and scratch/wound-closure migration assays in endothelial and fibroblast cell lines; endothelial tube-formation angiogenesis assays.
Molecular & Technical Profile
C212H350N56O78S | MW 4963.44 g/mol | CAS 77591-33-4 | Sequence: 43-amino-acid synthetic analogue of Thymosin Beta-4 (Tβ4)
Storage, Reconstitution & Working Concentrations
Storage, reconstitution, and working-concentration values are general laboratory guidance for in vitro and animal research; always confirm against the lot-specific Certificate of Analysis.
Current Research Status
As of the time of this writing, TB-500 has not been approved by the U.S. Food and Drug Administration (FDA) for any human therapeutic use. The available evidence base is primarily preclinical, derived from rodent, porcine, and in vitro models. Thymosin Beta-4 has been the subject of limited early-phase clinical investigation in narrow ophthalmic contexts, but translation to broader human clinical contexts has not been established through controlled clinical trials. Ongoing research continues to characterize the compound's mechanistic profile and identify which experimental findings may have translational relevance.
Research FAQ
Is TB-500 approved for human use?
No. TB-500 has not been approved by the FDA for any human therapeutic use. The evidence base is preclinical (rodent, porcine, and in vitro models), with only limited early-phase clinical investigation of Thymosin Beta-4 in narrow ophthalmic contexts. The compound is supplied for laboratory research use only — not for human consumption.
What is TB-500's molecular formula and sequence?
A synthetic 43-amino-acid analogue of Thymosin Beta-4 — molecular formula C212H350N56O78S, MW 4963.44 g/mol, CAS 77591-33-4.
How is TB-500 stored and reconstituted?
Store lyophilized at −20°C, protected from light and moisture. Reconstitute in sterile water for injection or bacteriostatic water; store the reconstituted solution at 2–8°C for up to ~21 days (or aliquot and freeze at −80°C) and avoid repeated freeze–thaw cycles.
What targets and model systems has TB-500 been studied in?
Preclinical work has characterized Thymosin Beta-4 in relation to G-actin sequestration, ILK/Akt signaling, the NF-κB pathway, and TGF-β signaling, across dermal wound, corneal epithelial, myocardial infarction, ischemic limb, and in vitro cell-migration and angiogenesis model systems.
Selected References
- Goldstein et al. — Overview of Thymosin beta4 multi-functional regenerative properties across tissue systems. Expert Opin Biol Ther, 2012.
- Safer et al. — Identification of Thymosin beta4 as the major actin-sequestering peptide in mammalian cells. J Biol Chem, 1991.
- Philp et al. — Thymosin beta4 and a synthetic tetrapeptide AcSDKP promote dermal and epidermal healing in excisional wounds. Wound Repair Regen, 2003.
- Sosne et al. — Thymosin beta4 suppresses cytokine-induced NF-kappaB activation in corneal epithelial cells. Invest Ophthalmol Vis Sci, 2006.
- Malinda et al. — Thymosin beta4 measured for stimulation of endothelial cell migration and tube formation in in vitro angiogenesis assays. FASEB J, 2003.
- Malinda et al. — Thymosin beta4 assessed for acceleration of full-thickness dermal wound healing in rodent models. FASEB J, 1999.
- Bock-Marquette et al. — Thymosin beta4 activation of integrin-linked kinase (ILK) measured in cardiac progenitor cell survival and neovascularization assays. Nature, 2004.
- Bock-Marquette et al. — Thymosin beta4 mediated Akt phosphorylation and endothelial cell sprouting quantified in ischemic limb revascularization model. Ann N Y Acad Sci, 2006.
- Smart et al. — Thymosin beta4 assessed for epicardial progenitor cell activation and coronary vasculogenesis in embryonic and adult mouse hearts. Nature, 2011.
- Sopko et al. — Thymosin beta4 assessed for reduction of infarct size, apoptosis, and improvement of cardiac function in murine myocardial infarction model. J Mol Cell Cardiol, 2011.
- Hinkel et al. — Thymosin beta4 measured for collateral vessel density and left ventricular function improvement in porcine model of chronic ischemia. Ann Thorac Surg, 2008.
- Petsophonsakul et al. — Thymosin β4 anti-fibrotic mechanisms assessed via TGF-β pathway modulation and collagen deposition markers across tissue models. Int Immunopharmacol, 2023.
- Sosne et al. — Thymosin beta4 quantified for suppression of TNF-α and IL-1β-driven inflammatory cytokine cascades in corneal cell model. Exp Eye Res, 2007.
- Goldstein et al. — Review of Thymosin beta4 safety profile, tolerability observations in preclinical species, and regulatory status. Ann N Y Acad Sci, 2012.
- Florian et al. — Phase I clinical trial measuring safety, tolerability, and pharmacokinetic endpoints of Thymosin beta4 in healthy volunteers. Ann N Y Acad Sci, 2014.