Dry skin lacks oil or sebum, while dehydrated skin lacks water. Dry skin is a skin type that is usually genetic, while dehydrated skin is a skin condition that can be caused by environmental factors such as weather, air conditioning, or heating. To address dry skin, you need to focus on nourishing and moisturizing your skin with products that contain hydrating ingredients like glycerin, ceramides, and hyaluronic acid. Vichy's MINÉRAL 89, which is a fortifying and hydrating daily skin booster hyaluronic acid serum, is an excellent product to use for dehydrated skin.