Melanin doesn’t just help determine our appearance—it also protects our skin against damage from the sun. The sun emits ultraviolet (UV) light that can damage our skin, leading to sunburns and even skin cancer.
Skin cancer is a disease caused by damage to the DNA inside our skin cells. DNA can be damaged when it absorbs energy from UV light. Skin cancer does not happen every time the DNA in our skin is damaged, but the more it is damaged the more likely it is that cancer can develop.
The melanin in skin cells can absorb UV light as the light enters the cells, before it gets to the nucleus where it can damage the DNA. The more melanin there is inside a cell, the more energy is absorbed before UV light can reach the nucleus and cause damage. This means that people with a lot of melanin in their skin have more protection against skin damage from UV light.