At one time, women could get a lasting younger look only by a surgical facelift. Then came skin-rejuvenation techniques that produced more natural-looking results: dermabrasion, chemical peels, and ablative laser resurfacing. In these procedures, the outer layers of skin are removed (ablated) to spur wound healing and the growth of new collagen and skin cells ( see "Skin structure and skin aging"). But the process hurts, and recovery can take days or weeks.
On the skin's outermost layer — the paper-thin epidermis — old cells continually die, flake away, and are replaced by younger cells that rise up from the lower epidermis. This process renews the skin about once a month.
Beneath the epidermis is a thicker layer called the dermis, which contains substances such as collagen and elastin, and structures such as blood vessels, oil glands, and nerves. Collagen, a structural protein, is arranged in layers of fiber called fibrils, forming a matrix that holds the skin together. Elastin, a protein similar to collagen, gives skin its elasticity. Beneath the dermis is a layer of fat.
As we age, the dead cells don't slough off as easily, so the surface of the skin becomes rougher. Less moisture is retained and less collagen and elastin are produced, so the fibril layers loosen and become less organized, causing skin to sag. Losing collagen and elastin, the skin becomes thinner, so fine lines appear around the eyes, and deeper lines occur at the mouth and across the forehead.
All these changes are accelerated by exposure to sun. In fact, damage from sun exposure, also called photoaging or photodamage, is the source of most facial lines and wrinkles. Smoking also prematurely ages the face by damaging collagen and elastin and impairing blood circulation to the skin.
There are several newer ways to tighten skin and improve its tone and texture with less recovery time and usually less discomfort: non-ablative laser treatments, intense pulsed light, and radiofrequency resurfacing. These techniques work below the skin surface, on the dermal level, usually without injuring the outer layers of the skin. But most of them rely on some degree of heat damage to deeper skin layers for their rejuvenating effects. One, Thermage, uses radiofrequency waves to heat collagen deep in the dermis, causing the strands to contract and tighten the skin surface. It causes some pain, but recovery time is less than a day.
There's also a technique that doesn't heat or damage deep skin layers. Called light-emitting diode (LED) photomodulation, it involves the use of low-level light to treat photoaged (sun-damaged) skin. It has less dramatic effects than many other skin-rejuvenation approaches, but it’s painless, and requires no recovery time. LED photomodulation appears to work best on skin with mild to moderate sun damage. Patients report tighter pores, fewer wrinkles around the eyes and mouth, and overall improvement in skin quality and texture. Clinicians are also using LED photomodulation in combination with other skin-improvement techniques, although it's unclear how effective this is.
