Dry skin is a result of lack of natural sebum (oil) production. Skin can feel rough and tight due to an unhealthy skin barrier, which means individuals with naturally dry skin need extra care to help stimulate oil production. The goal with this skin type is to use products that stimulate oil production and are occlusive, which helps repair and strengthen the skin's barrier.
Dehydrated skin is a lack of water in the skin. This can happen due to over-exfoliation, harsh product use, medications, and the environment. The goal with this skin type is to use products that help keep the skin hydrated. Using products with humectants will draw water back into the skin while occlusive products will help prevent transepidermal water loss (TEWL).