TB-500
Thymosin β4 fragment
Overview
TB-500 is a 43-amino-acid synthetic peptide derived from Thymosin β4 (the actin-sequestering protein expressed natively in nearly every mammalian cell type). The molecule's biological activity centers on actin-binding via its central LKKTETQ motif and downstream effects on cellular migration, angiogenesis, and tissue regeneration, the mechanistic basis for the broad TB-500 research literature on wound healing, cardiac remodeling, and tendon-ligament repair models. TB-500's longer sequence relative to BPC-157 makes it serum-stable but not orally bioavailable, so research workflows are exclusively injectable-route. TB-500 is on the July 2026 FDA PCAC agenda for 503A bulks-list consideration with the proposed indication of wound healing. Lyochem supplies TB-500 acetate as a lyophilized powder at ≥99.0% HPLC purity. The 43-residue sequence is at the upper-middle range for routine SPPS, synthesis is reliable but purification cycles are more demanding than for shorter peptides like BPC-157, and the analytical packet emphasizes peak-integration HPLC plus mass spec to clear deletion sequences that elute close to the target peak. Sequence verification by LC-MS/MS is available on request and is the recommended qualification test for any TB-500 supplier, for a 43-mer, mass alone leaves more identity ambiguity than for a 15-mer like BPC-157. TB-500 is most commonly ordered as the standalone vial or as the Wolverine Blend with BPC-157 (5+5 mg per 10 mg vial standard, custom ratios via OEM). For the full BPC-157 vs TB-500 mechanism and analytical comparison, see our [side-by-side article](/lab-notes/bpc-157-vs-tb-500-side-by-side); for the 503A regulatory context, see our [503A vs 503B compounding guide](/lab-notes/503a-vs-503b-compounding-pharmacy-peptides).
Who buys this, and why
Repair peptides — BPC-157, TB-500, B7-33, PEG-MGF — ship primarily to research labs studying tissue-repair, gastrointestinal-mucosa, tendon-ligament, and vascular-endothelial models. The synthesis itself is reliable, but analytical confirmation is where suppliers differ: buyers qualifying a new source should request sequence verification by tandem MS on the first lot and compare against the labelled sequence directly.
Primary buyer fit: research laboratories that have validated this peptide into their workflow and academic and contract research laboratories.
Specifications
- CAS
- 885340-08-9
- Sequence
- SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES
- Appearance
- White lyophilized powder
- Purity (HPLC)
- ≥ 99.0%
- Common vial sizes
- 2 mg, 5 mg, 10 mg
- MOQ
- On request
- Lead time
- 7–14 days
- Storage
- -20°C, protect from light
Documentation available on request
- Lot-specific Certificate of Analysis (CoA)
- RP-HPLC chromatogram with peak integration
- ESI-MS identity confirmation (±0.5 Da)
- Sequence verification by LC-MS/MS
- Water content by Karl Fischer
- SDS / MSDS
- Counter-ion analysis (acetate vs TFA)
- Solubility / reconstitution guidance
- Stability data at −20 °C on request
Regulatory note
Currently under FDA PCAC review (July 2026) for inclusion on the 503A bulks list, with the proposed indication of wound healing.
Frequently asked questions
What is TB-500 and how does it differ from native Thymosin β4?▾
TB-500 is a 43-amino-acid synthetic peptide derived from a defined region of native Thymosin β4 (which is a 44-residue protein in mammals). The synthetic TB-500 sequence includes the LKKTETQ actin-binding motif that drives the molecule's biological activity. Compared with native Thymosin β4 produced recombinantly, the synthetic TB-500 is more economically accessible at research and commercial scale and avoids the variability that comes with cell-line-expressed material. The biological activity per mass is functionally equivalent for the actin-binding and tissue-regeneration readouts that dominate the TB-500 research literature.
Why is sequence verification more important for TB-500 than for shorter repair peptides?▾
TB-500 is 43 amino acids, which is at the upper-middle end of routine SPPS. Longer peptides accumulate more single-residue deletion sequences during synthesis, and those deletion products elute close to the target peak on RP-HPLC, they pass the standard HPLC purity gate but are not the molecule the buyer ordered. Mass spec alone catches identity to within 0.5 Da but cannot distinguish between, say, a [Lys-deletion at position 12] and a [Lys-deletion at position 30] of equal residue mass. LC-MS/MS sequence verification with full b- and y-ion ladder coverage is the only test that directly demonstrates the synthesized sequence matches the labelled sequence, recommended at first-time supplier qualification for any 40+ residue peptide.
What's the practical difference between using TB-500 alone vs. the Wolverine Blend with BPC-157?▾
TB-500 and BPC-157 act through different molecular mechanisms, TB-500 is an actin-binding peptide affecting cellular migration and tissue remodeling, while BPC-157 acts through nitric-oxide-pathway modulation and growth-factor-receptor cross-talk. The two are commonly combined in research and compounding contexts because the mechanisms are complementary rather than redundant. The Wolverine Blend SKU bundles both peptides into a single co-lyophilized vial at a standard 5+5 mg ratio (custom ratios available); the combined vial simplifies handling and the analytical packet certifies both components in a single document.
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