This narrative review examines emerging antioxidant science through the framework of network redox biology. Rather than treating antioxidants as interchangeable radical scavengers, it emphasizes localization, regeneration, membrane access, metabolic support and disease context as determinants of biological relevance. The article focuses on ferroptosis as a turning point in antioxidant research because it links iron-dependent lipid peroxidation with membrane failure and highlights defense nodes such as GPX4-glutathione, FSP1-CoQ-NAD(P)H, GCH1-BH4 and sterol-related radical trapping. It also discusses melatonin-related antioxidant cascades, molecular hydrogen, mitochondrial and compartment-aware protection, catalytic nanozymes, mechanism-matched biomarkers and disease-oriented translation. Overall, the review argues that antioxidant value should be assessed by fit within a defined redox circuit rather than by a single in vitro assay value.