Oxidative Stress in Health and Disease: Mechanisms and Therapeutic Perspectives

Reactive oxygen species (ROS) are inevitable byproducts of aerobic metabolism that exert a dual role in biological systems. At physiological levels, tightly regulated ROS levels function as essential signaling molecules regulating cellular communication, immune defense, metabolic adaptation, and maintenance of tissue homeostasis. However, excessive or deregulated ROS production disrupts redox balance and contributes to oxidative stress, a key factor in the onset and progression of numerous pathogenesis. This review provides an updated and integrated overview of ROS biology, summarizing their major types, cellular and molecular sources, and physiological functions, highlighting their significance in physiological redox signaling and oxidative stress-mediated disease mechanisms. Key molecular pathways involved in ROS-induced cell damage, redox imbalance, and signaling dysregulation are discussed. In addition, contemporary and emerging approaches for the detection and quantification of ROS and oxidative stress in clinical and preclinical samples—such as biochemical assays, fluorescent probes, biosensors, and advanced imaging techniques—are critically evaluated. The contribution of oxidative stress to the pathophysiology of major disorders, including cancer, diabetes, cardiovascular diseases, neurodegenerative conditions, and inflammatory disorders, is also examined. Finally, this review highlights future perspectives in precision redox medicine, emphasizing the potential of targeted antioxidant-based diagnostic and therapeutic strategies supported by advances in ROS detection technologies and a deeper understanding of redox-regulated biological processes.