TB-500 (Thymosin β4 fragment)
BPC-157 and TB-500: How They Differ
Reviewed by our laboratory team · Last updated 2026-07-03
BPC-157 and TB-500 are distinct peptides. BPC-157 is a 15-residue pentadecapeptide isolated from gastric juice with multi-pathway studied mechanisms. TB-500 is a synthetic fragment of Thymosin Beta-4 studied primarily for actin sequestration. They differ in origin, sequence, and mechanism.
Key facts
- BPC-157 origin
- Gastric juice pentadecapeptide
- TB-500 origin
- Thymosin Beta-4 fragment
- Length
- BPC-157: 15 aa; TB-500: fragment of 43 aa parent
Are they used together in research?
Some tissue-repair research examines each independently; joint use is described in some grey literature but limited peer-reviewed data supports combination protocols.
Extended research context
The TB-500 (Thymosin β4 fragment) deep dive
Deep dive: TB-500 vs full-length Thymosin Beta-4
'TB-500' is a synthetic peptide corresponding to the active 17-amino-acid actin-binding region of the endogenous 43-residue Thymosin Beta-4 protein. The two are not identical — TB-500 lacks the flanking sequence that gives full-length TB-4 additional binding partners. In the research literature, papers use 'Thymosin β4' when they mean the full protein and 'TB-500' or 'AcSDKP fragment' when they mean the shorter synthetic peptide. Reading a CoA carefully to see which molecule is in the vial matters — mass spec is the definitive check.
Actin-binding as the core mechanism
The N-terminal region of TB-4 (and TB-500 by inheritance) contains the canonical actin-binding motif. This motif sequesters G-actin monomers, modulating the G:F actin equilibrium in cell cultures. That mechanism is why almost every mechanistic paper on TB-500 traces back to cytoskeletal reorganisation, cell migration, and models of tissue repair.
Handling considerations unique to TB-500
TB-500 is a 17-residue peptide with modest amphipathicity; it reconstitutes cleanly in bacteriostatic water but is sensitive to repeated freeze/thaw. Aliquoting into single-use volumes on first reconstitution preserves potency across a batch. HPLC on the batch CoA should show a single dominant peak; a doublet suggests deamidation.
Research applications
- ▸In vitro actin-polymerisation assays (G:F actin ratio measurement)
- ▸Cell-migration and wound-scratch assays in fibroblast lines
- ▸Angiogenesis models: tube-formation and endothelial migration assays
- ▸Analytical method development for short peptides on RP-HPLC
- ▸Reference-material comparisons against endogenous Thymosin β4
Handling checklist
- ✓Store lyophilised vials at −20 °C long-term
- ✓Reconstitute with bacteriostatic water (0.9% benzyl alcohol)
- ✓Aliquot immediately to avoid freeze/thaw cycles
- ✓Refrigerate reconstituted aliquots at 2–8 °C; use within 28 days
- ✓Confirm mass (~4,963 Da for TB-500) via CoA before study use
Common research-handling mistakes
Learnt from thousands of researcher orders across our UK labs.
✗ Assuming TB-500 = full Thymosin β4
Fix: TB-500 is the 17-residue actin-binding fragment; check the CoA sequence.
✗ Repeated freeze/thaw
Fix: Aliquot at first reconstitution; each cycle degrades yield.
✗ Using tap water
Fix: Use bacteriostatic or sterile water only.
Continue researching
Peer-reviewed guides, comparators and matched reference materials.
Related questions researchers ask
- Is TB-500 the same as Thymosin Beta-4?
- How does TB-500 bind actin?
- What is the molecular weight of TB-500?
- How is TB-500 reconstituted for research?
- Is TB-500 legal to buy in the UK for research?
Frequently asked questions
- Do they share a mechanism?
- No — they act via different molecular pathways.
Primary sources & clinical trials
Peer-reviewed research and registered trials from PubMed, ClinicalTrials.gov, PubChem, FDA and NIH. All links open in a new tab (external, rel="nofollow").
- PubMedPubMed — BPC-157 vs Tβ4pubmed.ncbi.nlm.nih.gov
- PubMedGoldstein et al., Thymosin β4: a multi-functional regenerative peptide — Ann NY Acad Sci 2012 (PMID 22574954)pubmed.ncbi.nlm.nih.gov
- PubMedCrockford et al., Thymosin β4 in acute myocardial infarction — Expert Opin Biol Ther (PMID 20095868)pubmed.ncbi.nlm.nih.gov
- PubMedSosne et al., Thymosin β4 corneal wound healing — Ann NY Acad Sci (PMID 20955324)pubmed.ncbi.nlm.nih.gov
- TrialClinicalTrials.gov · Thymosin β4 (RGN-259) dry eye Phase 3 (NCT03925727)clinicaltrials.gov
- PubChemPubChem · Thymosin β4 (CID 16132341)pubchem.ncbi.nlm.nih.gov
- PubMedNIH PubMed — Thymosin beta-4 tissue repairpubmed.ncbi.nlm.nih.gov
- GuidelineGoogle — Creating helpful, reliable, people-first contentdevelopers.google.com
More TB-500 (Thymosin β4 fragment) articles
- What Is TB-500? Research OverviewTB-500 is a synthetic peptide fragment of Thymosin Beta-4 studied for actin binding, cell migration, and angiogenesis in in vitro and animal models.
- TB-500 Peptide: Structure and OriginTB-500 peptide structure: a synthetic fragment of the 43-residue Thymosin Beta-4 protein. Sequence, origin, and relationship to native Tβ4 explained.
- TB-500 vs Thymosin Beta-4: The DifferenceTB-500 is a synthetic fragment of Thymosin Beta-4. Tβ4 is the full 43-residue native protein. Structural and research-context differences explained.
- What Does TB-500 Stand For?TB-500 stands for 'Thymosin Beta-500', a development code for a synthetic Thymosin Beta-4 fragment. Origin of the name and naming context explained.
- TB-500 Mechanism: Actin Sequestration ExplainedTB-500 mechanism: sequesters G-actin monomers via the LKKTETQ motif, regulating actin polymerisation dynamics. Molecular mechanism explained.
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- Bacteriostatic WaterWhat Is Bacteriostatic Water?Bacteriostatic water is sterile water containing 0.9% benzyl alcohol as a bacteriostatic preservative. The benzyl alcohol inhibits bacterial growth after the vial's initial puncture, making the same vial suitable for repeated withdrawal in research handling. It is not the same as plain sterile water.