What happens to skin when it is exposed to ultraviolet light?

It is important to protect your skin from overexposure to ultraviolet (UV) light to prevent the development of skin cancer, a known result of repeated sunburns over time. If the threat of an increased risk of basal cell carcinoma, squamous cell carcinoma and melanoma—the deadliest form of skin cancer—doesn’t resonate, overexposure also causes premature aging.

Dr. Ellen E. Marmur, MD
Dermatologist (Skin Specialist)

Melanocytes have the crucial job of producing melanin, the pigment that absorbs ultraviolet light from the sun. Ultraviolet wavelengths can damage or destroy the DNA in cells, causing mutations that can turn into cancers. Once the skin is exposed to sunlight, the melanocytes try to cover all the cells with melanin, like sun hats that block UV rays. Ironically, though most of us feel that a suntan is a beautiful sign of health, it's actually a visible response to skin trauma, since the pigment has been produced to shield our cells' DNA from danger. 

Simple Skin Beauty: Every Woman's Guide to a Lifetime of Healthy, Gorgeous Skin

Dr. Mehmet Oz, MD
Cardiologist (Heart Specialist)

When skin is exposed to ultraviolet (UV) light—the type of light in sunlight—several things happen. On the positive side, skin exposed to UV light makes vitamin D, an important nutrient. However, UV light also can cause an inflammatory reaction—a sunburn. In addition, UV light stimulates melanin cells in skin, causing them to darken; when this happens, you have a tan. Unfortunately, there is no such thing as a safe tan. The UV light that burns or tans you damages skin cells in ways that can accelerate skin aging, and even increase your risk of developing skin cancer. There are two kinds of UV light: Ultraviolet A (UVA) and ultraviolet B (UVB). UVA speeds skin aging and boosts skin cancer risk; UVB causes sunburn. 

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.