TB-500: Safety Profile & Research Summary
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Buy TB500 Peptide - all sizes29 PubMed CitationsExpert ReviewedLast Reviewed: February 2026
Preclinical Research Summary
Animal Studies (TB-500 Fragment Specifically)
| Study | Model | Key Findings | Ref |
|---|---|---|---|
| Rahaman et al. (2024) | Rat / fibroblasts in vitro | Metabolite Ac-LKKTE showed wound-healing activity — parent TB-500 did not. Primary metabolite Ac-LK at 0-6h, Ac-LKK to 72h. No cytotoxicity. | [17] |
| Philp et al. (2003) | db/db diabetic mice, aged mice | LKKTETQ fragment promoted dermal repair comparable to full-length Tβ4. ↑ wound contracture and collagen deposition. | [8] |
| Sosne et al. (2010) | In vitro (LDH assay) | No significant difference between acetylated TB-500 and non-acetylated LKKTETQ on cell injury (LDH release). | [24] |
| Ho et al. / Kwok et al. (2012-2013) | Thoroughbred horses | Single administration; detected at 0.02 ng/mL in plasma, 0.01 ng/mL urine. Detection: 11.3h plasma, 9.7h urine. | [25][26] |
Studies Using Full-Length Thymosin Beta-4 (Parent Molecule)
Note: These studies used the 43-amino acid full-length Tβ4 protein, not the TB-500 fragment. Results may not be directly transferable to the 7-amino acid fragment.
| Study | Model | Key Findings | Ref |
|---|---|---|---|
| Bao et al. (2013) | Rat myocardial ischemia | 5.37 mg/kg, long-term exposure — 43% infarct volume reduction (p < 0.01) | [21] |
| Bock-Marquette et al. (2004) | Mouse cardiac cells | Tβ4 activates ILK → promotes cardiac cell migration, survival, and cardiac repair (published in Nature) | [11] |
| Smart et al. (2007) | Mouse epicardial progenitors | Tβ4 induces epicardial progenitor mobilization and neovascularization (published in Nature) | [27] |
| Malinda et al. (1999) | Rat dermal wound | Tβ4 increased re-epithelialization by 42% over saline at 4 days post-injury | [18] |
| Shah et al. (2018) | Mouse liver fibrosis | Tβ4 prevented oxidative stress, inflammation, and fibrosis in ethanol/LPS liver injury | [16] |
Clinical Studies / Human Data (Full-Length Tβ4 Only)
No registered human clinical data exists specifically for the TB-500 fragment. The following are clinical data for the full-length Thymosin Beta-4 protein.
| Study | Design | n= | Key Outcome | Ref |
|---|---|---|---|---|
| RGN-352 Phase I | Healthy volunteers | 40 | Well tolerated over 14 days; no dose-limiting toxicities | [28] |
| RGN-259 Phase II (Dry Eye) | Phase II trial | — | Dry-eye sign and symptom endpoints reported | [19][20] |
| RGN-137 Phase II (Pressure Ulcers) | Phase II trial | — | Dermal-healing endpoints reported | [29] |
Pharmacokinetic Parameters
| Parameter | Value | Ref |
|---|---|---|
| G-Actin Binding | 1:1 stoichiometric complex (LKKTETQ motif) | [6] |
| ATP Synthase KD | ~12 nM (endothelial cell surface) | [10] |
| In vitro migration activity | ~50 nM (identical to full-length Tβ4) | [24] |
| Plasma Half-life | ~2.5–3 hours | [25] |
| Equine Detection | Plasma 11.3h, urine 9.7h (single administration) | [26] |
| Primary Metabolite | Ac-LK (0-6h), Ac-LKK (up to 72h) | [17] |
| Acute Toxicity Threshold | No toxicity observed up to 20 mg/kg | [3] |
Comparison: TB-500 (Fragment) vs. Thymosin Beta-4 (Full Protein)
| Feature | TB-500 (Ac-LKKTETQ) | Thymosin Beta-4 (Full) |
|---|---|---|
| Length | 7 amino acids (fragment 17–23) | 43 amino acids |
| Actin Binding | ✅ Retains LKKTETQ motif | ✅ Full actin-binding domain |
| Anti-Fibrotic (Ac-SDKP) | ❌ Absent (aa 1–4 not included) | ✅ Present via N-terminal Ac-SDKP |
| Cell Migration | Comparable (~50 nM) | Comparable (~50 nM) |
| Wound Healing | Via metabolite Ac-LKKTE | Direct + via Ac-SDKP |
| Human Clinical Data | None | Phase I/II (RGN-352, 259, 137) |
| FDA Status | Category 2 (prohibited) | IND (clinical development) |
The products offered on this website are furnished for in-vitro studies only. In-vitro studies (Latin: in glass) are performed outside of the body. These products are not medicines or drugs and have not been approved by the FDA to prevent, treat or cure any medical condition, ailment or disease. Bodily introduction of any kind into humans or animals is strictly forbidden by law.
For Laboratory Research Only. Not for human use, medical use, diagnostic use, or veterinary use.
ALL ARTICLES AND PRODUCT INFORMATION PROVIDED ON THIS WEBSITE ARE FOR INFORMATIONAL AND EDUCATIONAL PURPOSES ONLY.
In Vitro / Preclinical Disclaimer: The research findings described above were observed in laboratory (in vitro) and/or animal model studies. These results may not translate to human outcomes. No claims are made regarding human therapeutic applications.
Educational Use Only: This content summarises published laboratory and clinical literature for research reference only. It is not medical advice.
Editorial Research Note
“Preclinical Research Summary Animal Studies (TB-500 Fragment Specifically) StudyModelKey FindingsRef Rahaman et al.”
References
- Esposito S, Deventer K, Goeman J, Van der Eycken J, Van Eenoo P. Synthesis and characterization of the N-terminal acetylated 17-23 fragment of thymosin beta 4 identified in TB-500. Drug Testing and Analysis. 2012;4(9):733-738.
- Delcourt V, Garcia P, Chabot B, Bailly-Chouriberry L. TB500/TB1000 and SGF1000: A scientific approach for a better understanding of misbranded and adulterated drugs. Drug Testing and Analysis. 2023;15(4):458-464.
- Goldstein AL, Hannappel E, Sosne G, Kleinman HK. Thymosin β4: a multi-functional regenerative peptide. Expert Opinion on Biological Therapy. 2012;12(1):37-51.
- U.S. Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks. FDA.gov. Updated July 8, 2025.
- World Anti-Doping Agency. The 2025 Prohibited List. WADA. January 1, 2025.
- Xing Y, Ye Y, Zuo H, Li Y. Progress on the Function and Application of Thymosin β4. Frontiers in Endocrinology. 2021;12:767785.
- Bock-Marquette I, Maar K, Maar S, et al. International Immunopharmacology. 2023;116:109741.
- Philp D, Badamchian M, Scheremeta B, Nguyen M, Goldstein AL, Kleinman HK. Thymosin β4 and a synthetic peptide containing its actin-binding domain promote dermal wound repair in db/db diabetic mice and in aged mice. Wound Repair and Regeneration. 2003;11(1):19-24.
- Belsky JB, Rivers EP, Filbin MR, Lee PJ, Morris DC. Thymosin beta 4 regulation of actin in sepsis. Expert Opinion on Biological Therapy. 2018;18(sup1):193-197.
- Hinkel R, El-Aouni C, Olson T, et al. Thymosin beta4 is an essential paracrine factor of embryonic endothelial progenitor cell-mediated cardioprotection. Circulation. 2008;117(17):2232-2240.
- Bock-Marquette I, Saxena A, White MD, Dimaio JM, Srivastava D. Thymosin beta4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair. Nature. 2004;432(7016):466-472.
- Smart N, Risebro CA, Melville AA, et al. Nature. 2007;445(7124):177-182.
- Sosne G, Kleinman HK. Investigative Ophthalmology & Visual Science. 2015;56(9):5110-5117.
- Reyes-Gordillo K, Shah R, Popratiloff A, et al. Thymosin-β4 (Tβ4) Blunts PDGF-Dependent Phosphorylation and Binding of AKT to Actin in Hepatic Stellate Cells. American Journal of Pathology. 2011;178(5):2100-2108.
- Malinda KM, Sidhu GS, Mani H, et al. Thymosin beta 4 accelerates wound healing. Journal of Investigative Dermatology. 1999;113(3):364-368.
- Shah R, Reyes-Gordillo K, Cheng Y, et al. Oxidative Medicine and Cellular Longevity. 2018;2018:9630175.
- Rahaman KA, Muresan AR, Min H, et al. Simultaneous quantification of TB-500 and its metabolites by UHPLC-Q-Exactive orbitrap MS/MS and their screening by wound healing activities in-vitro. Journal of Chromatography B. 2024;1235:124033.
- Malinda KM, Sidhu GS, Mani H, et al. Thymosin beta 4 accelerates wound healing. Journal of Investigative Dermatology. 1999;113(3):364-368.
- Sosne G, Ousler GW. Clinical Ophthalmology. 2015;9:877-884.
- Sosne G, Dunn SP, Kim C. Cornea. 2015;34(5):491-496.
- Bao W, Ballard VL, Needle S, et al. Frontiers in Pharmacology. 2013;4:149.
- Treadwell T, Kleinman HK, Crockford D, et al. Annals of the New York Academy of Sciences. 2012;1270:37-44.
- Nguyen J, Verma S, Vuong VT, et al. Engineered Tandem Thymosin Peptide Promotes Corneal Wound Healing. Investigative Ophthalmology & Visual Science. 2025;66(14):31.
- Sosne G, Qiu P, Goldstein AL, Wheater M. Biological activities of thymosin beta 4 defined by active sites in short peptide sequences. The FASEB Journal. 2010;24(7):2144-2151.
- Ho EN, Kwok WH, Lau MY, et al. Doping control analysis of TB-500 in equine urine and plasma by liquid chromatography-mass spectrometry. Journal of Chromatography A. 2012;1265:57-69.
- Kwok WH, Ho ENM, Lau MY, Leung GNW, et al. Doping control analysis of seven bioactive peptides in horse plasma by liquid chromatography-mass spectrometry. Analytical and Bioanalytical Chemistry. 2013;405(8):2595-2606.
- Smart N, Risebro CA, Melville AA, et al. Nature. 2007;445(7124):177-182.
- RegeneRx Biopharmaceuticals. 2009.
- Treadwell T, Kleinman HK, Crockford D, et al. The regenerative peptide thymosin β4 accelerates dermal healing. Annals of the New York Academy of Sciences. 2012;1270:37-44.
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