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How are epidermal cells replaced as skin grows?

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A pangolin walks through grass with a blue circle around it and the word endangered written in white across the image. — Integument The pangolin is the only mammal in the world covered in scales.

Epidermal cells are replaced through a continuous process of cell division and upward migration. New keratinocytes are formed by mitosis primarily in the basal layer, which is the innermost region of the epidermis in contact with the dermis.123

As these cells are produced, they are pushed peripherally toward the skin surface. During this ascent, the cells undergo a series of structural changes: they move through the spinous and granular layers, where they begin to manufacture keratin and develop desmosomes to maintain structural integrity.13

By the time the cells reach the outermost layer, the stratum corneum, they have lost their nuclei and organelles, becoming flattened, keratin-filled dead cells. These cells are eventually shed from the surface in a process called desquamation. In healthy skin, the rate of cell production at the base is finely balanced with the rate of loss at the surface, ensuring the epidermis maintains a consistent thickness. The entire journey from formation to desquamation typically takes one to three months.12