Senolytic

FOXO4-DRI is a senolytic - a compound designed to kill senescent cells, the damaged cells that stop dividing but refuse to die and pump out inflammatory signals. It works by a clever trick: senescent cells stay alive because FOXO4 sequesters p53 in the nucleus, so the peptide is a retro-inverso decoy that breaks that interaction, p53 leaves the nucleus, and the cell kills itself. In the 2017 Cell paper that introduced it, it restored fitness, fur density and kidney function in fast-ageing and naturally aged mice. Nine years later there is still no human trial, no human pharmacokinetics and no human safety data of any kind. There is also a significant piece of counter-evidence: in pulmonary arterial hypertension models, eliminating senescent cells made the disease worse, not better.