TB-500[Thymosin beta-4 fragment]
Compound snapshot
Class
Synthetic fragment of thymosin beta-4
FDA approved
No — recommended 8–6 by the FDA advisory committee in July 2026, but not compoundable until rulemaking finishes
Clinical development
Preclinical
Last reviewed
September 2026
Research areas
Tissue repair / Gastrointestinal lining / Musculoskeletal recovery
Regulatory status
Research use only — not approved
Internet attention
High
Registry query
TB-500
A synthetic fragment of thymosin beta-4, a naturally occurring actin-binding protein present in nearly every human cell and in wound fluid.
Reality check — what we actually know
Supported by human evidence
- No adequately powered randomised human trials establish the outcomes this compound is marketed for.
Animal research only
- Faster cell migration into wound beds — the step that closes a wound
- Reduced scar tissue and fibrosis in animal models of skin, cornea and heart injury
- Improved flexibility and reduced adhesion around healing tendon in rodent work
Mechanistically plausible
- Binds G-actin and promotes actin polymerisation, which lets cells migrate into a wound. Also upregulates VEGF-driven angiogenesis and downregulates inflammatory cytokines, and has been studied for cardiac progenitor cell activation.
Common internet claims
- Online discussion frequently presents TB-500 as a proven treatment rather than a research compound.
Not established
- Human efficacy for the outcomes commonly claimed
- Optimal route, quantity and duration in humans
- Long-term human safety
Evidence distribution
Each band is a live PubMed search for TB-500, filtered to that kind of study. Top is the strongest evidence; the base is reasoning, not proof. A band with no records means that kind of study has not been published for this compound yet.
Mechanism and reported findings
Binds G-actin and promotes actin polymerisation, which lets cells migrate into a wound. Also upregulates VEGF-driven angiogenesis and downregulates inflammatory cytokines, and has been studied for cardiac progenitor cell activation.
- Faster cell migration into wound beds — the step that closes a wound
- Reduced scar tissue and fibrosis in animal models of skin, cornea and heart injury
- Improved flexibility and reduced adhesion around healing tendon in rodent work
- Anti-inflammatory effect on damaged tissue independent of steroids
- Corneal and dry-eye repair — the closest thing to human trial data, via the full thymosin beta-4 molecule (RGN-259)
Strength of the evidence: Strong mechanistic and animal data; human trials exist for the parent protein in eye and wound indications, not for the TB-500 fragment sold to consumers. WADA-prohibited.
Safety and known cautions
Same angiogenesis caution as BPC-157. Consumer TB-500 is not the molecule used in clinical trials.
Evidence at a glance
No single score, on purpose. The line beside each bar shows how much reported outcomes vary between studies.
Development stage
- Discovery
- PreclinicalCurrent
- Phase 1
- Phase 2
- Phase 3
- Regulatory review
- Approved