Directly cited from From Obagi Medical http://www.obagi.com/Homepage.aspx

When it comes to transforming aging skin, nothing else is Obagi Nu-Derm.
Throughout our lives we all experience occasional sunburns, regular sun exposure, hormonal changes, stress, and environmental pollution. All these factors contribute to the signs of premature aging. The Nu-Derm System has been formulated to improve the signs of aging at the cellular level.