TB-500
Also known as thymosin beta-4, TB4
A synthetic version of an actual human protein fragment, sold unregulated and studied mostly in animals.
$40–120 per vial on grey markets.
How it works
Thymosin beta-4 is a naturally occurring actin-sequestering peptide involved in cell migration, angiogenesis and wound repair. TB-500 is a synthetic fragment of it. Animal models show accelerated healing of muscle, tendon and cornea.
How it's used
No approved human indication. Human trials of thymosin beta-4 have been run for corneal and cardiac repair with mixed results, but the grey-market "TB-500" sold online is not that pharmaceutical product. Prohibited in tested sport.
Trade-offs
In favour
- Based on a real human signalling peptide
- Some legitimate clinical trial history for the parent molecule
- Encouraging animal healing data
Against
- Grey-market product is not the studied pharmaceutical
- No approved human use
- Banned in sport
- Long-term safety unknown
Risks and side effects
- Unregulated sourcing: purity and sterility unverified
- Angiogenesis promotion carries a theoretical tumour-growth risk
- Injection-site reactions and infection
- No meaningful human safety monitoring data
How good is the evidence?
Genuine clinical interest in thymosin beta-4 itself, but little human evidence for the grey-market peptide as used cosmetically or for recovery.
Sources
Sources point to guideline bodies and literature searches rather than single papers, so they stay accurate as the evidence moves.