Tanning is a sign that sun damage has occurred. It is triggered by exposure to both UVA and UVB light.
UVA rays are considered the dominant tanning ray. UVA light penetrate deep into the skin and can tan skin without burning. When skin is exposed to UVA radiation, sun damage is caused. The UV radiation triggers certain cells called melanocytes produces more melanin pigment, which tries to protect your cells from further damage by absorbing UV radiation from the sun. However, as your skin gets darker and your melanocytes divide in order to form additional protection, it is a sign that damage has already occurred. Additionally, as skin darkens, it increases the risk of mutations which can lead to skin cancer.
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