What is oxidative stress? Is cellular stress that leads to oxidate damage that has been implicated to lead to certain diseases such as cancer and Alzheimer’s. Oxidative stress is also recognized as having an impact on the body’s aging process. Oxidative stress within the body happens naturally due to the body’s own metabolic waste, producing free radicals. However, sources outside the body that include exposure to cigarette smoke and other environmental toxins lead to an added amount of free radical formation in the body that when out of balance can lead to disease and inflammatory reactions.