3. Skin Cells: A 2-3 Week Cycle
Your skin is in a state of constant renewal, with most skin cells living for just 2-3 weeks before being shed and replaced. This continuous cycle forms your body’s first line of defense against the outside world, protecting you from pathogens, UV rays, and physical injury. It’s also why wounds can heal quickly and why exfoliation—removing dead skin cells—leaves skin looking fresh. For more on skin cell turnover and its role in health, see Harvard Health.