There are three main layers of the skin: the epidermis, the dermis, and the hypodermis. The epidermis is the outermost layer of the skin, the dermis is the middle layer, and the hypodermis is the deepest skin layer that maintains our skin's hydration levels.
The dermis is where collagen and elastin, the proteins responsible for keeping skin flexible and plump, are produced. As a result, this layer of skin is directly responsible for many visible signs of aging, including thin skin.
Over time, elastin and collagen growth in the dermis naturally slows. In fact, once we reach 20 years old, we actually start to produce
1% less collagen each year. As a result, skin starts to thin and become more dehydrated and fragile with time.
Thinning skin can be difficult to treat, because all skin layers are affected by the decrease in elastin fibers and collagen molecules. As the dermis produces less collagen and elastin, the epidermis and hypodermis lose volume too. Older adults may notice dry and thinning skin on the face, hands, and feet especially, because these areas of skin are thinner than the rest of the body naturally, even in young, healthy people.