ROS / Reactive Oxygen Species / Oxidative Stress
Unstable molecules with unpaired electrons that cause oxidative damage to cellular structures including DNA, proteins and lipid membranes. In skin, free radicals are generated by UV radiation, pollution (PM2.5, ozone), smoking, metabolic processes and blue light. They directly degrade collagen and elastin, trigger inflammatory cascades that accelerate aging, and mutate DNA contributing to skin cancer. Antioxidants neutralise free radicals by donating an electron — which is why daily antioxidant serums (Vitamin C, Vitamin E, ferulic acid) are considered foundational for photoaged and urban skin.
A single UV photon can generate hundreds of free radical chain reactions. This is why UV protection plus antioxidants together outperform either alone — SPF reduces UV-induced free radical formation, while antioxidants neutralise those that get through.
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