How is photoaging formed? Light aging is the main reason caused by long-term uv radiation, ultraviolet irradiation intensifies the melanin cell, form a complex amino acid may, along with the continuous renewal of the new cell goes on to the skin surface, accumulate over a long period of pigmentation can form discoloration, ultraviolet ray also can make the skin microcirculation change at the same time, make the blood capillary expansion presents the status of local erythema, and make the elastic fibrous degeneration and conglobation blocky accumulation, can also affect the formation of collagen type Ⅰ Ⅲ type relative increase causes a decline in the mature collagen bundles of collagen, the skin sagging and wrinkles.