Dityrosine, an oxidation product of protein formed through the intermolecular cross-linking of tyrosyl radicals from the reactive oxygen species (ROS) and tyrosine interaction, is associated with decreased hippocampal expression of NMDA receptor subunits Nr1, Nr2a, and Nr2b when administered intragastrically at 320 µg/kg per day, leading to memory impairments in mice as evidenced by their performance in a novel object recognition test. Additionally, it raises fasting blood glucose levels while reducing plasma insulin levels and the pancreatic expression of insulin synthesis-related genes Ins2, Pdx1, and MafA. Increased dityrosine levels have been positively linked to a range of diseases, including autism spectrum disorder, cataracts, Alzheimer's disease, Parkinson's disease, atherosclerosis, and cystic fibrosis.