FOX04-DRI

FOXO4-DRI (FOXO4-D-Retro-Inverso) is a synthetically engineered peptide senolytic — a compound designed to selectively eliminate senescent cells. Cellular senescence is a state of stable cell cycle arrest that accumulates with age and in response to stress, contributing to chronic inflammation, tissue dysfunction, and age-related pathology. While senescent cells are not simply inert, their persistence in tissue is increasingly understood as a driver of multiple hallmarks of aging. The peptide takes its name from the FOXO4 transcription factor and its structural design: D-amino acids arranged in reverse sequence (retro-inverso) relative to a native FOXO4 segment. This configuration makes the peptide highly resistant to protease degradation compared to conventional L-amino acid peptides, an important pharmacological consideration for in vivo stability. The foundational proof-of-concept study, published in Cell in 2017 by Baar and colleagues, demonstrated that FOXO4-DRI could clear p16(INK4a)-positive senescent cells in mice, reverse markers of frailty in naturally aged animals, improve renal function in a progeroid mouse model, and restore fitness after chemotherapy-induced damage. These findings generated significant interest in the longevity research community and among self-experimenters, though the compound has not progressed to registered human clinical trials as of 2026. Because all published efficacy and safety data are derived from rodent models, the translational relevance to humans remains entirely unknown. FOXO4-DRI is an unregulated research compound, and its use outside controlled laboratory settings carries substantial and incompletely characterised risks.