A lack of what is characteristic of dry skin?

Dry skin is primarily characterized by a lack of oil, also referred to as sebum. Sebum is a natural oil produced by sebaceous glands in the skin, and it plays a crucial role in maintaining skin hydration and barrier function. When there is insufficient oil on the skin, it can lead to dryness, resulting in a rough texture, flakiness, and increased susceptibility to irritation and environmental damage.

While water levels and moisture are important for overall skin hydration, the absence of oil is particularly significant in defining dry skin conditions. Proteins, while important for skin structure and resilience, do not directly equate to skin dryness in the same way that oil deficiency does. Therefore, the defining characteristic of dry skin hinges on the lack of oil.