Ultimate Longevity Bible

Intervention

TB-500 (Thymosin Beta-4)

Last updated 2026-07-02· Last reviewed 2026-07-02· 1 min read

Reviewed by the Ultimate Longevity Bible editorial team. Educational reference — not medical advice. See disclaimer.

What it is

Thymosin beta-4 is a 44-amino-acid endogenous protein that binds G-actin and modulates cytoskeletal dynamics, cell migration, angiogenesis, and inflammation. TB-500 is a synthetic peptide encompassing the actin-binding site, sold to the peptide community.

Evidence

  • Preclinical: consistent signals for wound-healing acceleration, cardiac repair post-infarction, and neuroprotection in rodent models.
  • Human: essentially no RCT data. Anecdotal use in tendon injury and post-surgical recovery.
  • Regulatory: not an approved drug in any major jurisdiction; sold as a "research chemical".

Practical considerations

  • Manufacturing quality varies enormously — batch potency and endotoxin contamination are unpredictable outside pharmaceutical-grade compounding pharmacies.
  • Injectable route; sterile technique required.
  • Prohibited by WADA for competitive athletes.

Longevity relevance

TB-500 is a speculative longevity intervention. The mechanism is plausible; the human data are absent. Not comparable in evidence quality to rapamycin or metformin.

Related entries

Peptides overview, MOTS-c, Exercise.

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