You can't stand your dog's shedding problem. No matter how often you sweep, you find drifts of dander piled into every corner. Don't be so hard on the poor pooch, though; you shed too. In addition to the occasional hair you'll find swirling around your bathtub drain, you also scrub away your skin cells. As much as 75 percent of the dust that accompanies that dander is composed of your dead skin cells; in fact, almost nine pounds (four kilograms) of dead skin sloughs off of you each year [source: Reucroft and Swain].
The image of nine pounds of your dead skin in a pile on the floor is pretty gross, but it's part of a natural regenerative process. Dead skin cells are shed from the outermost layer of your skin's surface -- the stratum corneum, or horny layer. Beneath the horny layer are younger, living cells (called keratinocytes) that form the middle epidermal layer. As these keratinocytes die, they replace the cells shed from the horny layer. Below the keratinocytes is the basal layer, where new skin cells are born.
All three layers comprise the epidermis -- the outermost layer of your skin -- and follow their life cycle in an outward push from the bottom of the epidermis to the surface as they form, live, die (in a process called cornification), shed and become dust on your furniture. The horny layer of your skin isn't the most attractive; dead skin is often dry and dull-looking. One way to combat dry skin is to apply moisturizers, which rehydrate the dead skin cells. This solution, unfortunately, is but a temporary one.
You can also treat dry skin by hastening the process of shedding dead skin cells. You can find products designed to slough off the horny layer at drug stores and cosmetics counters. Both hydroxy acids and exfoliants remove cornified keratinocytes from your epidermis, revealing the living cells beneath.
Daily exfoliation sounds like a good idea, doesn't it? It turns out, though, that speeding up the natural process of shedding dead skin cells (known as desquamation) can be harmful when done too frequently.