How do antioxidant vitamins stabilize free radicals?

Antioxidant vitamins do not stabilize free radicals. Instead they donate an electron to the free radical, turning it into a more stable molecule that poses less cellular damage. Different antioxidant vitamins have different chemical characteristics that allow them to accomplish this. For instance, vitamin C will donate an electron from its hydroxyl (-OH) and in the process its double bond will change into a single bond. Vitamin A and vitamin E, which are tocopherols, both work in a similar way, donating an electron from their hydroxyl group and changing a double bond to a single bond. They donate multiple electrons as their multiple double bonds change into single bonds.