Reactive oxygen species (ROS) or free radicals occur all the time as a result of exposure to ultraviolet light, cigarette smoke, and polution. The bad effects of reactive oxygen species are that they can damage our DNA and other body structures over time resulting in aging.
For example, one free radical called superoxide attacks fatty acids in our cell membranes resulting in a yellow material called lipofuscin. When this accumulates in the skin, it gives the skin a dusky yellow hue which is characteristic in heavy smokers.
Our bodies protect themselves from oxidative stress using a variety of internal mechanisms including vitamin antioxidants such as vitamins A, C, and E. We can help reduce the production of reactive oxygen species by using topical antioxidants.
A partial list of topical antioxidants includes:
1. vitamin C
2. coffee berry extract
4. green tea extracts
Evaluating the effectiveness of these products is a tricky science. There best way to measure the antioxidant effect of a topical product is to measure the decrease in skin damage after UV radiation after it has been applied. However, this is labor intensive and rarely done.
The more common way to measure antioxidant activity is to use the ORAC score. This is a test tube evaluation that can not be directly applied to human biology. Thus, we have to use our best judgement to make sense of the knowledge available to choose the best antioxidants for our skin.