What is TB-500 (Thymosin β4)?
TB-500 is a research designation for a synthetic peptide related to thymosin β4 (Tβ4) — a naturally occurring 43-amino-acid peptide that is described in the literature as the major G-actin-sequestering molecule in eukaryotic cells. Thymosin β4 is found in almost every cell type and in body fluids such as blood plasma and wound fluid, where it has been studied for its role in cytoskeletal regulation and tissue repair.
The name TB-500 is used in the research-peptide community for thymosin β4 and, in particular, for its actin-binding region — the short central sequence LKKTETQ (residues 17–23). Published work has identified this region as an active site associated with actin binding, cell migration, angiogenesis, and wound-healing signaling. A current early-stage clinical trial registered on ClinicalTrials.gov even lists its intervention explicitly as "TB-500 (Thymosin Beta 4 17-23 Fragment)," reflecting how closely the designation is tied to this active site. Throughout this guide the compound is discussed strictly as a laboratory research material — it is not a medicine and is intended for research use only.
The essentials at a glance
Thymosin β4-related peptide
TB-500 is associated with thymosin β4, a naturally occurring 43-amino-acid peptide and the major G-actin-sequestering molecule in cells.
Actin, migration & angiogenesis
Studied in preclinical models for cell migration, angiogenesis, and the actin regulation that underlies tissue-repair research.
Tissue-repair research
Investigated across dermal, corneal, and cardiac repair and regeneration models — as characterized in the published literature.
99%+ verified purity
HPLC-verified and confirmed by LC-MS, with a batch-specific certificate of analysis — research use only.
Explore research-grade TB-500
HPLC-verified to 99%+ purity, batch-specific COA, fast U.S. shipping — for laboratory research use only.
View TB-500How TB-500 is studied: the actin-binding mechanism
Thymosin β4 draws research interest primarily because of its relationship with actin, the protein that builds the cellular cytoskeleton. These mechanisms describe how the peptide is characterized in published scientific literature — they describe what is being studied, not confirmed outcomes:
- G-actin sequestration — thymosin β4 binds monomeric (globular, or G-) actin in a 1:1 complex, acting as an intracellular actin buffer that holds a reserve of actin monomers and helps regulate their assembly into filaments.
- The actin-binding domain (residues 17–23) — research has localized much of the peptide's cell activity to a short central sequence, LKKTETQ, identified as an active site linked in studies to angiogenesis, wound healing, and cell migration.
- Cell migration & cytoskeletal remodeling — by influencing the pool of polymerizable actin, thymosin β4 has been studied in cultured-cell models for its association with cell motility, spreading, and directional movement.
- Angiogenesis — the peptide has been investigated for associations with new blood-vessel formation and endothelial-cell behavior, including signaling pathways such as Notch and NF-κB in preclinical ischemia models.
The recurring theme across these areas is actin regulation and cell migration — processes central to how tissue-repair and angiogenesis models are studied. This is why thymosin β4, and the TB-500 designation associated with its active region, is so often referenced in preclinical repair and recovery research rather than in any single, narrow context.
What the research explores
In preclinical laboratory research, thymosin β4 and its active fragment are most often studied across a handful of interconnected areas:
- Dermal wound models — reepithelialization, collagen deposition, and keratinocyte migration in preclinical skin-repair research.
- Corneal & ophthalmic models — corneal-wound and ocular-surface research, the area where thymosin β4 has advanced furthest toward the clinic.
- Cardiac repair models — preclinical studies examining vessel growth, cell survival, and activation of resident cardiac progenitor cells after injury.
- Angiogenesis & limb-ischemia models — new blood-vessel formation and endothelial-cell behavior in preclinical vascular research.
- Actin & cytoskeletal biology — the foundational cell-migration and actin-regulation research from which the peptide's other research areas follow.
Clinical status: largely preclinical and early-stage
It is important to be precise about where thymosin β4 sits scientifically. The large majority of the evidence base is preclinical — cell-culture and animal-model research — and the compound is not an approved therapy for any indication. Where human research exists, it is early-stage and, in several programs, has produced mixed or incomplete results.
- Ophthalmic program (RGN-259) — a topical thymosin β4 eye-drop candidate developed by RegeneRx Biopharmaceuticals and its partner ReGenTree has been evaluated in phase 2 and phase 3 trials for dry-eye disease (the ARISE program) and neurotrophic keratopathy (the SEER program). Results across these trials have been mixed, with some endpoints met and others not.
- Cardiac program — recombinant human thymosin β4 (e.g., NL005) has been studied in early-phase trials for acute myocardial infarction, while earlier systemic programs did not advance.
- Fragment program — a phase 1/2 study of a TB-500 (thymosin β4 17–23) fragment candidate in cardiovascular research began recruiting in 2026.
TB-500 vs. BPC-157
TB-500 and BPC-157 are the two most-searched "repair and recovery" research peptides, and researchers frequently place them side by side. The clearest way to compare them is by their origin and the mechanism each is most associated with — they are distinct molecules studied for overlapping but different reasons:
| Compound | Origin / class | Primary research focus |
|---|---|---|
| TB-500 (Thymosin β4) | Peptide related to thymosin β4 — a 43-aa actin-sequestering protein | Cell migration, actin regulation, angiogenesis, tissue-repair models |
| BPC-157 | Synthetic pentadecapeptide (gastric-juice-derived partial sequence) | Tissue-repair, angiogenesis, and gastrointestinal models |
| Wolverine (BPC-157 · TB-500) | Multi-peptide research blend | Combined repair and recovery research |
Both are studied in tissue-repair research, but they originate from different parent proteins and are examined for different primary mechanisms — thymosin β4 for its actin-binding and cell-migration activity, and BPC-157 for its gastric-juice-derived, angiogenesis-associated profile. Peptora carries research-grade TB-500 alongside BPC-157, and the Wolverine blend that combines the two. Each ships with its own batch-specific certificate of analysis.
Purity, handling & certificates of analysis
In research, the reliability of a result depends on the identity and purity of the material behind it. Every batch of TB-500 from Peptora is HPLC-verified to 99%+ purity, confirmed by LC-MS identity testing, and screened across a full quality-control panel before release. Each order ships with a lot-specific certificate of analysis (COA) so the exact vial in hand can be matched to its documentation.
TB-500 is supplied as a lyophilized (freeze-dried) powder. Before research use it is reconstituted with bacteriostatic water, which is sold separately. Careful handling preserves peptide integrity and the validity of downstream work:
- 1Allow the sealed vial to reach room temperature before opening.
- 2Add bacteriostatic water slowly down the inside of the vial wall; swirl gently and never shake.
- 3Let the powder dissolve completely before drawing any solution.
- 4Store the reconstituted solution refrigerated and protected from light.
Full step-by-step protocols live in the reconstitution guide and the storage guide. To understand what each figure on a report means, see the guide on purity and certificates of analysis and the overview of testing standards.
Scientific references
The literature below is provided for educational context, per PubMed and ClinicalTrials.gov, and describes preclinical and early-stage clinical research on thymosin β4 — which remains investigational and has not been established as a therapy in large, completed human clinical trials — as distinct from the laboratory research product supplied by Peptora.
- 1Goldstein AL, Hannappel E, Kleinman HK. Thymosin β4: actin-sequestering protein moonlights to repair injured tissues. Trends Mol Med. 2005;11(9):421-429. doi:10.1016/j.molmed.2005.07.004 (PMID: 16099219).
- 2Huff T, Müller CS, Otto AM, Netzker R, Hannappel E. β-Thymosins, small acidic peptides with multiple functions. Int J Biochem Cell Biol. 2001;33(3):205-220. doi:10.1016/s1357-2725(00)00087-x (PMID: 11311852).
- 3Sosne G, Qiu P, Goldstein AL, Wheater M. Biological activities of thymosin β4 defined by active sites in short peptide sequences. FASEB J. 2010;24(7):2144-2151. doi:10.1096/fj.09-142307 (PMID: 20179146).
- 4Malinda KM, Sidhu GS, Mani H, et al. Thymosin β4 accelerates wound healing. J Invest Dermatol. 1999;113(3):364-368. doi:10.1046/j.1523-1747.1999.00708.x (PMID: 10469335).
- 5Lv S, Cai H, Xu Y, et al. Thymosin-β4 induces angiogenesis in critical limb ischemia mice via regulating Notch/NF-κB pathway. Int J Mol Med. 2020;46(4):1347-1358. doi:10.3892/ijmm.2020.4701 (PMID: 32945357).
- 6Shrivastava S, Srivastava D, Olson EN, DiMaio JM, Bock-Marquette I. Thymosin β4 and cardiac repair. Ann N Y Acad Sci. 2010;1194:87-96. doi:10.1111/j.1749-6632.2010.05468.x (PMID: 20536454).
- 7Sosne G, Dunn SP, Kim C. Thymosin β4 significantly improves signs and symptoms of severe dry eye in a phase 2 randomized trial. Cornea. 2015;34(5):491-496. doi:10.1097/ICO.0000000000000379 (PMID: 25826322; ClinicalTrials.gov: NCT01393132).
- 8Clinical development (ClinicalTrials.gov): topical thymosin β4 / RGN-259 for dry eye — NCT02597803 (ARISE-1), NCT03937882 (ARISE-3); for neurotrophic keratopathy — NCT05555589 (SEER-2); recombinant human thymosin β4 in cardiac research — NCT05485818.
Explore research-grade TB-500
HPLC-verified to 99%+ purity, batch-specific COA, fast U.S. shipping — for laboratory research use only.
View TB-500Key takeaways
- TB-500 is a research designation for a synthetic peptide related to thymosin β4 (Tβ4), a naturally occurring 43-amino-acid protein and the major G-actin-sequestering molecule in cells.
- The name is closely tied to thymosin β4's actin-binding region — the LKKTETQ sequence (residues 17–23) — which published work identifies as an active site for actin binding, cell migration, and angiogenesis.
- In research it is studied across cell-migration, angiogenesis, and tissue-repair models (dermal, corneal, and cardiac) — as characterized in the literature, not as claims of outcomes.
- The evidence base is overwhelmingly preclinical or early-stage; thymosin β4 is investigational and not an approved therapy, and it is supplied for laboratory research use only.
- Peptora's TB-500 is HPLC-verified to 99%+ purity with a lot-specific certificate of analysis in every order, and is supplied as a lyophilized powder reconstituted with bacteriostatic water.
Frequently asked questions
This article is intended solely as an educational summary of publicly available scientific literature. Products offered by Peptora are supplied exclusively for laboratory research purposes and are not approved for human or veterinary use. The information presented should not be interpreted as medical advice, treatment recommendations, or clinical guidance.
