Free radicals are known as “reactive oxygen species”, or ROS. They are produced when your body uses oxygen for energy. Just as fire emits smoke as a by-product, ROS are emitted from the conversion of oxygen to energy in the human body, eventually causing oxidative damage to body systems. Free radicals are also created when the body is exposed to sun, pollution, car exhaust and other harmful environmental toxins. Other mediums include stress, as well as things that people put into their bodies, such as alcoholic beverages, unhealthy foods and cigarette smoke.