The FOXO4 peptide in a DRI conformation (D amino acids in a retro reversed sequence), henceforth named FOXO4 DRI, competes with FOXO4 for p53 binding in a dose dependent manner and doing so with higher affinity. FOXO4 DRI improves spermatogenesis in aged mice through reducing senescence associated secretory phenotype secretion from Leydig cells ScienceDirect FOXO4 DRI Peptide: Benefits and Dosage PEP DOSE Senolytics against Aging: Snapshot of a Fast Moving Field Josh Mitteldorf Frontiers FOXO4 DRI regulates endothelial cell senescence via the P53 signaling pathway