The skin acts as the body’s first line of defense against external threats. However, as we age, the epidermis—the outermost layer of skin—gradually becomes thinner and loses its protective strength. About 90% of the cells in this layer are keratinocytes, which originate from deeper layers of the epidermis and migrate upward, ultimately forming the skin’s protective barrier.
Study finds vitamin C boosts skin thickness by reactivating growth genes
