How does the shedding of old skin help to prevent acne?

Shedding old skin cells, which most people do naturally and invisibly, prevents them from plugging up pores. As new skin cells are formed underneath, the old cells eventually move up to the skin's surface where they fall off, usually every 28 days. For some reason, people who have acne have trouble shedding the cells inside their pores. The dead cells end up mixing with other substances, such as bacteria and the oil secreted by tiny glands in the skin. This mixture swells inside the pore until it erupts into a whitehead, a blackhead, or an infected pimple. To disrupt this process, some acne products help speed up the removal of dead skin cells.