People often mistake skin oil for skin hydration. Skin oil is the waxy substance, called sebum, that is secreted by the sebaceous glands to help maintain the barrier function of the skin. Skin hydration is the process wherein water is absorbed into the layers of the skin, known as the epidermis and dermis, to maintain its plumpness, elasticity, and resiliency.
it’s important to understand just how useful the right moisturizer can be. In normal and oily skin, external factors such as pollution, UV rays and excessive cleansing can damage skin’s moisture barrier, causing loss of moisture and an increase in oil production. Skipping moisturizer altogether and focusing on harsh acids that dry out the skin can actually cause oil glands to go into overdrive. As a result, your complexion can start to look even more oily.