TB-500

A research-market fragment of a naturally occurring actin-regulating peptide. Animal wound-healing data exist for Tβ4; the specific TB-500 product sold online is not a characterized human drug.

TB-500 is a synthetic peptide corresponding to the actin-binding motif of thymosin beta-4. Full-length Tβ4 sequesters G-actin and has been studied in wound and cardiac models; the fragment is assumed to carry some of that biology. Assumption is doing a lot of work.

Thymosin beta-4 has a genuine preclinical and some early clinical wound literature. TB-500 as marketed is a shorter fragment with far weaker documentation. Sports anti-doping agencies have flagged Tβ4/TB-500 for a reason: use without evidence, not use with evidence.

Not FDA-approved. WADA-prohibited. Research-chemical distribution only.

Not approved. Same 2023 Category 2 history as other regenerative peptides; July 2026 PCAC recommended 503A listing (non-binding). No lawful US consumer pharmacy product. WADA prohibits thymosin beta-4 and fragments.

Same four pathways as the Sourcing guide.

None.

Sold as TB-500 or 'thymosin beta-4 fragment' to athletes and injury forums. The marketed heptapeptide is not a characterized drug, and sports testing agencies treat it as a prohibited agent.

Strand does not list vendors. See the grey market.

Uncharacterized in humans at research-chemical doses. Angiogenic and cell-migration effects are double-edged in the setting of cancer. Sterility and sequence fidelity of gray-market vials are unknown.

• Uncharacterized in humans at research-chemical doses.
• Angiogenic and cell-migration effects are double-edged with cancer biology.
• Anti-doping sanction risk for tested athletes.
• Identity of grey-market fragments is not guaranteed.

• Tβ4 wound biology · 2005 · Trends Mol Med

  Goldstein, Hannappel, Kleinman. Thymosin β4: actin-sequestering protein moonlights in repair. PMID 15967722.

• WADA prohibited list

  Thymosin beta-4 and fragments are prohibited in sport.