What helps prevent the skin from drying out?

Sebum plays a crucial role in preventing the skin from drying out. It is an oily substance produced by sebaceous glands that are found in the dermis layer of the skin. This natural oil helps to create a barrier on the skin's surface, which locks in moisture and prevents water loss. Additionally, sebum has emollient properties, which can contribute to the skin's softness and smooth texture.

While other substances mentioned, such as sweat and oil from hair follicles, can provide some level of moisture or lubrication, they are not as effective as sebum in maintaining the skin’s hydration. Sweat primarily functions in thermoregulation and, although it can provide temporary moisture, it evaporates quickly, which does not help in retaining long-term hydration. Melanin, on the other hand, is primarily responsible for skin pigmentation and does not contribute to moisture retention.