TB-500 (Thymosin beta-4 fragment)
Sleep & Recovery · Synthetic peptide
Tier D
What this is
RegeneRx Biopharmaceuticals pursued clinical development; most programs stalled. Popular in horse racing (multiple high-profile positive tests) and bodybuilding peptide stacks. Vendors often sell full TB-4 rather than the fragment despite the name. Same FDA Jan 2025 compounding restriction as BPC-157; treat consumer supply as unverified research-peptide exposure.
Mechanism
Fragment (or sometimes full-length) of TB-4, an endogenous actin-sequestering peptide; proposed to promote cell migration, angiogenesis, and wound healing
Dose & route
2-5 mg subQ weekly (anecdotal)
Citations
- https://pubmed.ncbi.nlm.nih.gov/22420962/
- https://pubmed.ncbi.nlm.nih.gov/21415437/
- https://www.fda.gov/media/174456/download
- https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks
Links go to the source. If a link is dead or you want something re-checked, let me know.
This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.