With the passing of time, changes occur in four different aging zones.
Beneath the epidermis is the dermis. There are tiny veins called capillaries, which bring blood flow to the skin. There are sweat glands, hair bulbs and nerve endings. And, there are collagen and elastin fibers, which give strength and support to skin. Like the epidermis, the dermis undergoes major changes related to the aging process. Collagen and elastin fibers begin to break down, leading to sagging, or crepiness of the skin. Compounding this, collagen- and elastin-producing cells called fibroblasts become less active. Your skin can't make the amount of collagen fibers necessary to maintain your skins status quo, let alone repair damage. Sunlight is also harmful to the dermis, damaging cellular DNA. This can lead to an increased formation of blood vessels. Skin becomes more fragile and easily bruised. GAGs (glycosaminoglycans), a cellular component that helps give the skin overall structure, begins thinning along with the extracellular cement, which holds cells together. Some age-related lentigos are caused by melanin deposited into the dermis, similar to what is seen with some birthmarks. That is why the bleaching process can be so difficult (or even impossible) for some women.
Below the dermal layer is a layer of fat. As we age, the fatty layer on the backs of the hands, the neck and the face becomes noticeably thinner. The results are more noticeable blood vessels on the backs of the hands. Dark circles exacerbated by fat pad atrophy beneath the eyes. Overall thinning of the skin, allowing for increased fragility. Fat will accumulate, however, along the jowls, creating the waddle (double chin) and heavy looking, sagging lower cheeks.
Below the fat lies muscle. Deep wrinkle lines on the face are caused by the buildup of facial muscles through overuse, typically smiling and frowning or chronic puckering from smoking, which can cause deep lines to form around the mouth. But even a non-smoking lifetime of puckering can eventually form these deep, crevice-like lines, particularly if there has been substantial sun damage over time.
When it comes to skin rejuvenation, it's important to both understand where the issue exists on an anatomical level as it is to know what you are trying to accomplish.
Using this approach you can match the therapy to the problem. There is no single fix-it-all solution that tackles every aging skin issue. Targeted treatment takes education and the ability to literally read between the lines.