Oxidative stress is a direct consequence of an excess in the body of so-called free radicals—reactive, unstable molecules that contain oxygen. Free radicals are normal metabolic by-products and also help to relay signals in the body. In turn, oxidative stress (an overload of these molecules) can be caused by lifestyle, environmental, and biological factors such as smoking, high alcohol consumption, poor diet, stress, pollution, radiation, industrial chemicals, and chronic inflammation.

When this occurs, it creates an imbalance between the production of free radicals and the body’s antioxidant defenses, which are responsible for neutralizing them.