TB-500 (Thymosin Beta-4 Fragment): Research Peptide Guide (2026)
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Introduction (research-only scope)
TB-500 is a synthetic peptide derived from thymosin beta-4 (Tβ4), a 43-amino-acid actin-sequestering protein present in nearly all mammalian cells. In the research literature the names are often used loosely: TB-500 as sold is a synthetic material catalogued at molecular mass 4963.50 (CAS 77591-33-4, the CAS of thymosin beta-4), and the mechanistic and animal literature is written about thymosin beta-4 itself. This guide sets out that relationship, what the literature reports, and how to source and verify research-grade material.
Research use only. The material described here is a laboratory reagent for in-vitro research by qualified professionals. It is not a medicine, supplement, cosmetic ingredient or veterinary product, is not for human or animal use, and nothing on this page is medical advice or a claim of effect in any person.
What is TB-500?
Thymosin beta-4 was characterised by Allan Goldstein’s group in the 1980s and is the most abundant member of the beta-thymosin family. Its central actin-binding motif (LKKTETQ) is responsible for sequestering G-actin, which is the biochemical basis for its role in cell migration. Peptra Labs supplies TB-500 as a lyophilised research reagent, 5 mg per vial; the reagent is a synthetic material for in-vitro study of this biology, not the endogenous protein preparation used in clinical trials.
How the reported mechanism works
Actin sequestration and cell migration
By binding monomeric actin, Tβ4 regulates the pool available for polymerisation and thereby influences cytoskeletal dynamics and cell motility, the property most consistently reported across models.
Integrin-linked kinase and cardiac cell survival
A 2004 Nature paper reported that Tβ4 activates integrin-linked kinase and promotes cardiac cell migration and survival in a mouse model, the study that anchored much of the subsequent tissue-repair interest.
Anti-inflammatory and remodelling signals
Reviews of the animal literature describe reduced inflammatory signalling and modulation of matrix remodelling in dermal, corneal and cardiac models; the 2010 Annals of the New York Academy of Sciences volume collects this work.
What the published evidence covers
The evidence is deep in animal and in-vitro models and limited in humans; the human trials that exist used the full-length recombinant protein or specific formulations, not the synthetic research reagent. Independent replication outside the originating groups is scarcer than the volume of citations suggests, the same caution we apply across the catalog. Our page on TB-500 in tissue repair and the comparison BPC-157 vs TB-500 go into the study designs.
TB-500 vs BPC-157
The two are constantly paired in tissue-repair discussions and are frequently studied together; the 2026 rat Achilles tendon study we covered in news reported that pairing them added no measurable advantage over either alone in that model. Mechanistically they differ: BPC-157 is a gastric-juice-derived pentadecapeptide with reported vascular and nitric-oxide-related activity; TB-500 acts through actin dynamics. See BPC-157 vs TB-500.
How to verify a TB-500 research peptide is real and pure
Identity by mass spectrometry, purity by HPLC. Our specification is at least 98% purity. The published report for batch QY028 (tested 20 March 2026) reported 99.67% purity: Janoshik verification 121494. Match the batch number on your vial against the lab reports archive and read how to read a certificate of analysis.
Storage and reconstitution specific to TB-500
Store the lyophilised peptide sealed, dry and protected from light at 2 to 8 °C for routine use, colder for archiving. Reconstitute with bacteriostatic water, keep refrigerated and avoid repeated freeze-thaw. General handling is in the peptide storage protocol.
Regulatory status (FDA, EMA, WADA)
TB-500 is not an authorised medicine in the EU or the US. Unlike most compounds in this catalog, thymosin beta-4 and its fragments are named on the WADA Prohibited List (section S2.3, growth factors: “thymosin-u03b24 and its derivatives”), so material must not be used in the context of sport in any form; the live WADA list is the binding reference. The research reagent supplied here is for in-vitro laboratory use only. See the peptide risk profile.
Why labs choose our TB-500
A batch-tested reagent (QY028: 99.67%), 5 mg per vial, EU shipping with tracking, VAT included. Product page: TB-500 5 mg; buyer guide: Buy TB-500 in Europe.
References
- Bock-Marquette I et al. Thymosin beta4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair. Nature. 2004. PubMed 15565145
- Crockford D et al. Thymosin beta4: structure, function, and biological properties supporting current and future clinical applications. Ann N Y Acad Sci. 2010. PubMed 20536467
- Philp D, Kleinman HK. Animal studies with thymosin beta4, a multifunctional tissue repair and regeneration peptide. Ann N Y Acad Sci. 2010. PubMed 20536453