Also known as thymosin β4 acetate, tβ4 · Wikipedia
TB-500 is the research-chemical label most commonly applied to a synthetic peptide associated with the actin-binding region of thymosin beta-4 (Tbeta4). On vendor labels it may refer to a 17-amino-acid 'active fragment' containing the LKKTETQ motif, to a different short fragment, or to full-length 43-aa Tbeta4 - product identity is frequently inconsistent. It is positioned for injury recovery, tendon/ligament repair, and wound healing on the basis of preclinical and limited phase 2 clinical data on full-length Tbeta4. It is WADA-prohibited at all times under S2 (peptide hormones and growth factors) and has no human regulatory approval. Also known as Thymosin beta-4 acetate.
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Browse all vendorsMechanism of action
Full-length thymosin beta-4 (43 aa) is an actin-sequestering protein that reversibly binds G-actin to maintain a pool of unpolymerized monomer available for cytoskeletal remodeling, and it promotes cell migration, angiogenesis (via VEGF), and wound healing in dermal, corneal, and cardiac models (https://pubmed.ncbi.
Pharmacokinetic properties
Half-life
approximately 2-3 hours systemic, but tissue-residence and downstream effects appear longer (days)
Routes
subcutaneous · intramuscular
Bioavailability
Not orally bioavailable. Injected forms distribute systemically; depot-like sustained effects on healing are reported but not formally quantified.
Amino-acid sequence
(Thymosin beta 4; 43 aa) 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
Use & research dosing
No human regulatory dose exists. In self-experimentation reports, totals of 2-5 mg per week subcutaneously or intramuscularly are most commonly described, either as a single weekly injection or split across two doses, often structured as a 4-8 week loading phase followed by a lower maintenance dose every 2-4 weeks. Cycles are typically tied to a specific tendon or soft-tissue injury rather than continuous use. Research framing only.
Research-use framing only. SavePeptides sells nothing for human consumption. Doses above reflect reported research / self-experimentation ranges, not clinical recommendations.
Important labeling issue: 'TB-500' on research-chem labels almost never matches a single defined sequence. Some vendors ship full 43-aa Tbeta4 acetate, others ship a 17-mer actin-binding fragment, and some ship undefined shorter sequences. Buyers should treat 'TB-500' and full Tbeta4 as effectively interchangeable in commercial practice while recognizing that they are mechanistically and pharmacokinetically distinct. The most rigorous clinical work (phase 2 trials in epidermolysis bullosa, pressure ulcers, venous stasis ulcers, dry eye) used full-length Tbeta4, not the 17-mer.
— SavePeptides editorial desk · last updated 2026-05-25
Cautions & contraindications
Research foundation
Facts verified
2026-05-25
Confidence
medium
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