Sebum is the natural oil responsible for keeping your skin hydrated and supple. Everyone's body system is unique, and in some people, the sebaceous glands responsible for producing sebum simply do not make enough of the oil to counteract all of the drying elements present in the environment, such as cold, winter air. Without adequate hydration, your skin can become dry, resulting in redness, roughness and flaking. Dry skin is also more susceptible to sensitivity and more prone to show signs of premature aging. The Kerstin Florian Rehydrating collection was developed to address the unique needs of dry skin to help it look and feel its best.