The human skin sheds and replaces its entire outer layer every month
The human body completely replaces its entire outer layer of skin every 28 days, shedding millions of dead cells daily to maintain a waterproof barrier.
The skin is the body's largest organ, covering roughly two square meters and acting as a primary defense against infection and dehydration. This barrier is maintained by a relentless cycle of mitosis in the basal layer, where new keratinocytes are born and pushed toward the surface over a period of four weeks.
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