How does skin achieve a tanned appearance?

Skin achieves a tanned appearance primarily through the increased production of melanin in the outer layer of the skin. When exposed to ultraviolet (UV) radiation from sunlight or artificial sources, the skin's melanocytes—cells located in the epidermis—respond by producing more melanin. This pigment acts as a natural sunscreen, providing some protection against further UV damage. The more melanin that is produced, the darker the skin appears, resulting in an overall tanned look.

The stimulation of melanin production is a protective response to UV exposure and is a key factor in the tanning process. Understanding this mechanism is crucial for recognizing how tanning works and the implications it has for skin health and safety, such as the risk of skin damage and skin cancer associated with overexposure to UV light.