Comparison · Updated
TB-500 VS Thymosin Beta-4
Short answer
Thymosin Beta-4 has stronger published evidence than TB-500: tier A (Controlled human trials) vs tier C (Animal data).
Neither TB-500 nor Thymosin Beta-4 is FDA-approved.
Both are prohibited in sport by WADA under section S2.
01
Side by side
| Field | TB-500 | Thymosin Beta-4 |
|---|---|---|
| Evidence tier | C Tier C · Animal data | A Tier A · Controlled human trials |
| Tier rationale | No human trials of TB-500 itself; supporting data come from animal studies and from research on full-length thymosin β4. | Randomized, placebo-controlled phase 2/3 trials have been run in humans (RGN-259 eye drops for dry eye and neurotrophic keratopathy; RGN-137 for chronic wounds); not approved. |
| FDA status | Not approved | Not approved |
| Other approvals | None listed | None listed |
| WADA | Prohibited · S2Peptide hormones, growth factors, related substances and mimetics | Prohibited · S2Peptide hormones, growth factors, related substances and mimetics |
| Family | Repair | Repair |
| Residues | Not on file | Not on file |
| Molecular weight | Not on file | Not on file |
| Formula | Not on file | Not on file |
| Discovered | Not on file | 1981Isolated from calf thymus (thymosin fraction 5) by Goldstein and colleagues. |
| Routes studied | Subcutaneous, Intramuscular | Subcutaneous, Intramuscular |
| Mechanism | TB-500 (thymosin beta-4 fragment) sequesters G-actin monomers and promotes actin polymerization, which drives cell migration and wound healing. It upregulates cell surface integrins and promotes angiogenesis, enabling new blood vessel formation at injury sites. | Thymosin beta-4 is a 43-amino-acid actin-sequestering protein that regulates cell motility by modulating actin polymerization. It promotes tissue repair through activation of integrin-linked kinase (ILK) and Akt survival pathways, while also suppressing inflammatory cytokines and promoting stem cell recruitment. |
| Safety notes | Limited human safety data. | Phase II clinical trial data suggest acceptable safety. |
| Cited studies | 0 studies | 0 studies |
02
Questions
- Which has stronger evidence, TB-500 or Thymosin Beta-4?
- Thymosin Beta-4 has stronger published evidence than TB-500: tier A (Controlled human trials) vs tier C (Animal data). TB-500: No human trials of TB-500 itself; supporting data come from animal studies and from research on full-length thymosin β4. Thymosin Beta-4: Randomized, placebo-controlled phase 2/3 trials have been run in humans (RGN-259 eye drops for dry eye and neurotrophic keratopathy; RGN-137 for chronic wounds); not approved. Tiers rate the strength of published evidence, not effectiveness.
- Is TB-500 FDA-approved?
- TB-500 is not FDA-approved.
- Is Thymosin Beta-4 FDA-approved?
- Thymosin Beta-4 is not FDA-approved.
- Are TB-500 and Thymosin Beta-4 banned in sport?
- Both are prohibited in sport by WADA under section S2.
- How do TB-500 and Thymosin Beta-4 work?
- TB-500 (thymosin beta-4 fragment) sequesters G-actin monomers and promotes actin polymerization, which drives cell migration and wound healing. Thymosin beta-4 is a 43-amino-acid actin-sequestering protein that regulates cell motility by modulating actin polymerization.