OBAGI NU DERM SUNFADER SPF15 ~ Step #6 Over the years, your skin has been exposed to a number of environmental stressors, which cause damage that can reach the deepest layers of your skin. Photodamage, caused by the sun’s harmful rays, is the main cause of the fine lines, wrinkles and age spots that you may already see or you will eventually see on your face. As the #1 prescription-strength, physician-dispensed skin care system, the Nu-Derm System can actually transform your skin at the cellular level. By addressing the signs of photodamage and restoring the healthy function of your skin cells, this system is clinically proven to result in younger- and healthier-looking skin.