Free radial neutralisation. Animation showing the antioxidant vitamin C (orange) neutralising free radicals and thus preventing them from causing any cellular damage. Free radicals are molecules that contain unpaired electrons (bright spheres), making them highly reactive. They are a by-product of a number of biochemical reactions that occur in the body. They cause damage to various cellular components by stealing an electron to complete their pair. Antioxidants prevent this oxidation. HD supplied with alpha, or for a flat version on a black background, see clip K003 3708.