Safety Research

Animal studies do not confirm that TB-500 directly reactivates dormant tumors in humans, but they raise a biologically credible concern. Preclinical data show that thymosin beta-4 — the endogenous peptide TB-500 mimics — upregulates VEGF, activates pro-invasive signaling in cancer cell lines, and is overexpressed in several human tumor types. No controlled human trial has tested this risk.