Freckles are clusters of concentrated melaninized cells which are most easily visible on people with a fair complexion.

The exposure to UV-B radiation activates melanocytes to increase melanin production, which can cause freckles to become darker and more visible.

Heavily distributed concentrations of melanin may cause freckles to multiply and cover an entire area of skin, such as the face.

The variant Val92Met arose somewhere between 250,000 and 100,000 years ago, long enough for this gene to be carried by humans into central Asia.

[9] The need was less as humans moved into higher latitudes where incoming sunlight has lower UV light content.

The adaptation of lighter skin is needed so that individuals in higher latitudes can still absorb enough UV for the production of vitamin D.[9] Freckled individuals tend to tan less and have very light skin, an adaptation to allow individuals that expressed these genes to synthesise sufficient vitamin D. Ephelides describes a freckle that is flat and light brown or red and fades with a reduction of sun exposure.

Liver spots (also known as sunspots and lentigines) look like large freckles, but they form after years of exposure to the sun.

[11] This perception changed after the mid-20th century, when a tan, and the freckles associated with it, came to be desired as a status symbol indicating a life of leisure.

[10] Freckles became increasingly fashionable in the late 20th century as a result of the 1960s "youthquake" movement and through association with popular figures such as the model Twiggy and the musician Jane Birkin.