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TB-500: Research Overview

What is TB-500? TB-500 is a synthetic peptide based on Thymosin β4 (Tβ4), a naturally occurring 43-amino-acid protein. The name most commonly refers to the actin-binding fragment of Tβ4 — residues 17–23, the LKKTETQ region. It is studied in preclinical cell and animal models of actin regulation, cell migration, and tissue repair, and is sold strictly for laboratory research use.
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Important distinction: TB-500 ≠ full-length thymosin β4

Real human studies exist for thymosin β4 — including Phase 2 venous-ulcer work (73 patients) and a randomized ophthalmic trial (RGN-259). These should not be automatically attributed to every commercial material marketed as “TB-500.” Molecular identity, sequence and analytical confirmation matter. VP presents TB-500 by its documented analytical identity, not by borrowed thymosin β4 results.

Thymosin β4 human trials: PubMed 20536470; PubMed 36613994.

Technical profile

CompoundTB-500 (Thymosin β4 fragment)
ClassSynthetic peptide fragment of a naturally occurring protein
Sequence originActin-binding region of Thymosin β4 — residues 17–23 (LKKTETQ)
Parent proteinThymosin β4 (Tβ4): 43 amino acids, molecular weight ~4963 g/mol. The TB-500 fragment is substantially shorter; commercial material labeled "TB-500" may denote the fragment or full-length Tβ4 — the batch COA states which is supplied
Form suppliedLyophilized powder, sealed vial
StorageLyophilized: 2–8 °C, protected from light.
VerificationHPLC purity ≥99%, sterility, endotoxins, heavy metals — documented on the batch COA

Evidence at a glance

Research evidence is not one category. Human, animal (preclinical) and in-vitro / mechanistic data differ in strength — often sharply. VP Peptides separates them so no single line overstates the whole picture. Ratings are deliberately conservative and describe the published evidence base, not any effect in humans.

Human clinical
Insufficient
Animal / preclinical
Established
In-vitro / mechanistic
Moderate
Regulatory statusNot FDA-approved. On July 23, 2026 the Pharmacy Compounding Advisory Committee voted 8-6 to recommend it for the 503A bulks list (non-binding, pending HHS); FDA scientific staff stated they identified no human clinical studies of TB-500 for the proposed use.
What remains unknown
  • Commercial ‘TB-500’ (a synthetic actin-binding fragment) should not be equated with full-length endogenous thymosin β4 — most human trial data belong to the parent peptide, not TB-500
  • No human clinical studies identified for TB-500 itself; human efficacy and safety unestablished
  • Identity, purity and content of research-grade material not standardized

What does the research literature cover?

Thymosin β4 is one of the most abundant actin-sequestering molecules in mammalian cells, and its actin-binding fragment has been examined across a body of preclinical work. Published cell and animal studies have looked at:

Important context: the published evidence base is preclinical (cell and animal models). TB-500 has no approved human use in any jurisdiction, and rigorous human clinical trial data are lacking. Summaries here describe what researchers have studied — they are not claims about effects in humans.

Why purity matters for TB-500 research

Peptide research results are only as reliable as the material in the vial. Truncated sequences, deletion impurities, or endotoxin contamination confound experimental outcomes — and with TB-500 the fragment-versus-full-length distinction makes identity verification especially important. Every VP Peptides TB-500 batch ships with a Certificate of Analysis documenting ≥99% HPLC purity plus sterility, endotoxin and heavy-metal testing from independent third-party testing.

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Frequently asked questions

Is TB-500 approved for human use?

No. TB-500 is not approved by the FDA or any other regulatory agency for human use. It is supplied strictly as a research chemical for in-vitro and laboratory investigation. It is not a drug, supplement, or food ingredient.

How does TB-500 differ from Thymosin β4?

Thymosin β4 is the naturally occurring full-length protein of 43 amino acids (~4963 g/mol). TB-500 most commonly refers to a synthetic fragment corresponding to its actin-binding region, residues 17–23 (LKKTETQ). In commercial research supply, "TB-500" is sometimes also used for full-length Tβ4 — the Certificate of Analysis identifies exactly which sequence a batch contains.

What is TB-500's status in competitive sport?

For informational purposes: TB-500 / Thymosin β4 is prohibited in competitive sport under the World Anti-Doping Agency (WADA) Prohibited List. This is a regulatory fact about sport, not a statement about effects; the compound is supplied solely for laboratory research.

How should TB-500 be stored in the lab?

Lyophilized vials should be kept at 2–8 °C and protected from light.

Actin regulation & the thymosin β4 distinction, in context

At the molecular level, thymosin β4 is best understood as an actin-buffering protein. It binds monomeric G-actin in a roughly one-to-one complex and holds a reserve of unpolymerized actin that cells can draw on when they rebuild the cytoskeleton. The short LKKTETQ segment — the same region that defines the commercial "TB-500" fragment — sits at the heart of this actin-binding activity. In preclinical work, that seven-residue motif has been reported to reproduce much of the parent protein's influence on endothelial cell migration and blood-vessel formation, tying a single actin-regulatory site to angiogenesis in laboratory and animal models [1]. Review literature frames full-length thymosin β4 as a cytoskeletal regulator that is also released after injury, where it has been examined in dermal, corneal and cardiac repair models [2].

This is exactly where a careful distinction matters. Commercial "TB-500" is a synthetic actin-binding fragment; it is not chemically identical to the full 43-amino-acid endogenous thymosin β4 protein. Because of that, the human study record built up around thymosin β4 cannot simply be transferred onto TB-500 — the two are related but distinct molecules, and analytical confirmation of what a vial actually contains is what ties any published result to a specific sequence. Read together, the evidence base is preclinical-dominant: mechanistic and animal-model data are its strength, while rigorous human clinical evidence for TB-500 itself remains insufficient. TB-500 is not FDA-approved and is described here strictly as a research compound — nothing here implies human use, dosing or a route of administration.

Selected research references

Related research compounds

Research use only. All products described on this page are furnished for laboratory research purposes only and are not for human or veterinary use, not for use in food or cosmetics, and not for any diagnostic or therapeutic application. Nothing on this page is medical advice or a claim of safety or efficacy in humans. Research summaries reference publicly available preclinical literature; specific citations are listed in the references above.