[noun] Each of us has a unique colour of skin created by a combination of several pigments that are collectively referred to as melanin. Melanocytes are the cells responsible for producing melanin. When exposed to UV rays, melanocytes increase their melanin production, leading to a change in the skin’s pigmentation: tanning. This plays a natural protective role, but too much exposure, along with other external factors, can lead to an imbalance in melanin production, giving rise to the appearance of dark pigment spots.