 In the human skin, melanogenesis is initiated by exposure to UV radiation, causing the skin to darken.Melanin is an effective absorbent of light; the pigment is able to dissipate over 99.9% of absorbed UV radiation.Because of this property, melanin is thought to protect skin cells from UVB radiation damage, reducing the risk of folate depletion and dermal degradation, and it is considered that exposure to UV radiation is associated with increased risk of malignant melanoma, a cancer of melanocytes (melanin cells).