Free radicals
DEFreie Radikale
Free radicals are atoms or molecules carrying one or more unpaired electrons, which makes them highly reactive. They arise from normal metabolism, immune activity, and external sources such as UV radiation, pollution, and tobacco smoke. By stealing electrons from neighbouring molecules, free radicals damage membranes, enzymes, and DNA. The free-radical theory of ageing posits that this cumulative damage contributes to functional decline and age-related disease.