The skin is composed of three layers: a deep layer called hypodermis, a middle layer called the dermis and a surface layer called the epidermis.
The epidermis gives immediate, visible clues to the condition and health of the skin, while the dermis determines how the skin responds and changes with age. The hypodermis, the deepest layer, contains a layer of fat, blood vessels and nerves.
The dermis is composed mostly of collagen and elastin, which are proteins that give skin structure, strength, and flexibility. As we age, collagen and elastin production diminishes. The results show up on the face as a loss of firmness, rougher texture, more obvious wrinkles and sagging.
Hair follicles, nerves, blood vessels and sebaceous glands are also part of the dermis. Sebaceous glands produce sebum. This oily substance moves through the hair shaft to the top layer of the skin, where it covers the epidermis and provides a protective barrier against moisture loss. Too much sebum results in oily skin.
The epidermis is several layers deep. Basal cells are created in the lowest layer and then migrate through a hardened layer to the stratum corneum, from which they fall off the body.
The skin continually sloughs off the dead cells and grows new, living cells. It takes about a month for living basal cells to move to the top layer of the epidermis. As the cells move toward the surface of the skin, it loses moisture and oxygen content.
On the surface of the epidermis is a layer of oil transported from the dermis by the hair follicles that form a natural barrier, helping the skin to retain water.
Harsh and scented cleansing products, exposure to chemical and biological pollution the environment and poor diet can remove this protective oil-based layer from the skin.
This layer can be replenished with moisturizer.
Moisturisers work in several ways. First, they fill in the spaces between the relatively dry, or cornified cells of the epidermis, making the skin feel and appear smoother. They also create a barrier on the skin, helping the retain water.
The oil content in moisturizers works with the protective lipid from the air. Care must be taken in the selection and use of moisturizing products, as they make a huge difference in how the skin works.
Hydration is the key to smooth, even skin, and moisturisation is the external way to achieve it.