Cellular Repair & Recovery
TB-500
Thymosin beta-4 fragment
TB-500 (Thymosin Beta-4 fragment)
Research context
TB-500 corresponds to the active region of thymosin beta-4, a 43-residue actin-sequestering protein. Laboratory investigation centres on G-actin binding, cytoskeletal reorganisation, and endothelial cell migration, with published work in corneal and cardiac tissue models measuring migration distance and capillary density.
Common assays: G-actin binding · Endothelial migration · Capillary density quantification
Specification
| Designation | Thymosin beta-4 fragment |
|---|---|
| Full name | TB-500 (Thymosin Beta-4 fragment) |
| Sequence | Actin-binding domain fragment of thymosin beta-4 |
| CAS number | 885340-08-9 |
| Molecular formula | C212H350N56O78S |
| Molecular weight | 4963.44 g/mol |
| Formats | 10 mL Vial · 15 mL Advanced Liquid Peptide Spray |
| Solubility | Bacteriostatic water, sterile water |
| Storage | Lyophilised: −20 °C, desiccated. Reconstituted: 2–8 °C. |
| Regulatory status | Not an approved drug. Removed from FDA 503A Category 2 in April 2026 and recommended for the 503A bulks list by the advisory committee in July 2026. Since 30 October 2026, an HHS interim policy says the agency will not take enforcement action against licensed 503A compounding of it under set conditions. It has not been added to the bulks list. 2026 status by compound → |
| Current lot | TB10VCS0126 → |
TB-500 COA: certificates of analysis by lot
3 lots of TB-500 have a published certificate of analysis from AxisPharm, LLC, an independent laboratory. Each certificate reports the laboratory's results for that lot.
| Lot | Format | Purity (HPLC-UV) | Reported |
|---|---|---|---|
| TB24VBG0326 | 24 mg Vial | >99.3% | 2026-03-24 |
| TB10VCS0126 | 10 mg Vial | >99.2% | 2026-02-20 |
| TB30N1125 | 30 mg Spray | >99.0% | 2025-11-13 |
Published literature
Selected peer-reviewed references describing research involving this compound. Listed for reference only; inclusion is not a claim about any outcome.
- Goldstein AL, Hannappel E, Kleinman HK.Thymosin β4: actin-sequestering protein moonlights to repair injured tissuesTrends in Molecular Medicine · 2005 Find on PubMed ↗
- Malinda KM, Sidhu GS, Mani H, et al.Thymosin β4 accelerates wound healingJournal of Investigative Dermatology · 1999 Find on PubMed ↗
Common questions
How does TB-500 relate to thymosin beta-4?
TB-500 corresponds to the actin-binding region of the full 43-residue protein rather than the complete molecule. Much of the published activity of Tβ4 in migration assays has been attributed to this region.
Where can I see the TB-500 certificate of analysis?
Every published TB-500 lot has its own certificate page on this site, listed under "TB-500 COA" above. There are 3 published lots; the most recent, lot TB24VBG0326, was reported on 2026-03-24 at >99.3% purity by HPLC-UV. The certificates are issued by AxisPharm, LLC, an independent laboratory.
Components, blends and pathway
Related compounds
Wolverine
BPC-157 / TB-500
A prepared blend of the two most extensively studied compounds in the repair signalling literature.
KLOW
BPC-157 / TB-500 / GHK-Cu / KPV
A prepared four-component blend combining repair-signalling and cytokine-pathway compounds.
BPC-157
Body Protection Compound-157
A synthetic pentadecapeptide derived from a gastric juice sequence, studied in migration and angiogenesis models.
KPV
Lys-Pro-Val tripeptide
The C-terminal tripeptide of α-melanocyte-stimulating hormone, studied in NF-κB signalling.