TB-500 / Thymosin Beta-4
Also Known As: TB500, TB-500, Thymosin Beta-4, Tbeta4, Thymosin B4 Acetate, Thymosin β-4, TB-4, Tβ4, Thymosin Beta 4, T-beta4, Actin-sequestering peptide, Wound healing thymosin, Cardiac repair thymosin, LKKTETQ peptide motif, Thymosin beta4 synthetic, TB500 injection, thymosin beta 4, TB 500
TB-500 / Thymosin Beta-4 is a research-grade Endogenous 43-amino acid thymic peptide targeting G-actin sequestration studied in Healing & Recovery research. It is supplied strictly for in vitro laboratory research use only - not for human or animal consumption, and not FDA-approved.
Evidence Tier: Research Compound - No approved human use; sold for laboratory research only.
A research repair peptide that regulates the cytoskeleton; banned in sport and often mislabeled.
At A Glance
| Category | Healing & Recovery |
|---|---|
| Compound Class | Endogenous 43-amino acid thymic peptide; G-actin sequestrant and tissue-protection factor |
| Molecular Target | G-actin sequestration (Wiskott-Aldrich Syndrome protein WH2 domain); VEGF upregulation; integrin-linked kinase (ILK); thymosin beta-4 receptor (Tβ4R) |
| Molecular Weight | 4963.4 Da |
| Amino Acid Sequence | full Tbeta4 43 aa; TB-500 marketed fragment Ac-LKKTETQ |
| CAS Number | 77591-33-4 (Tbeta4) |
| Half-Life | ~30 hours |
| WADA Status | prohibited |
| Evidence Tier | Research Compound |
Mechanism Of Action
It binds to cellular actin, the protein responsible for cell movement. This heavily upregulates cell migration, allowing healing cells to travel quickly into damaged soft tissue to begin structural repair.
Studied For
- Dermal / corneal wound healing
- Cardiac repair models
- Tendon / ligament / muscle injury
- Hair growth stimulation
- Corneal healing / dry eye models
- Blood vessel formation
- Angiogenesis
- Bone repair
- Anti-inflammatory
- Nerve repair models
- Sports injury recovery
- Athletic recovery
- Post-surgical healing
- Scar tissue reduction
- Joint repair
- Muscle tear recovery
- GI healing
- Immune modulation
- Stem cell migration
- muscle recovery
- cardiac repair
- wound healing
- equine recovery
- tissue regeneration
- anti-inflammatory
- flexibility
- hair growth
- stem cell migration
Reported Research Findings
In vitro and animal data show wound closure, angiogenesis, and reduced scarring. Human data exist only for full-length Tbeta4 in early-phase trials and do not validate the injectable fragment products.
Safety And Handling Notes
Limited human safety data; pro-angiogenic theoretical tumor risk; immunogenicity; identity ambiguity between fragment and full-length.
Not approved. Prohibited by WADA since 2011 (class S2), at all times. Research use only.
Regulatory Status
Not FDA-approved. Named on the WADA 2026 Prohibited List under S2.3 as "Thymosin-beta4 and its derivatives e.g. TB-500"; prohibited at all times and a non-Specified substance.
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