Study Reveals Why UVB is More Damaging than UVA

According to a new research study published in the July 2008 Journal of The Federation of American Societies for Experimental Biology (FASEB), scientists now know why UVB light is more likely to cause skin cancer than UVA. This information could help to identify exactly how effective consumer products such as sunscreen are in preventing skin damage that leads to skin cancer. It may also allow scientists to pursue new lines of research and treatment to repair photodamage.

Ahmad Besaratinia, PhD, assistant research scientist at City of Hope National Medical Center, and first author on the report, said in the press announcement, “Our study is novel in that it fills the gaps in knowledge of mechanisms involved in sunlight-associated skin cancers, which cover various aspects of DNA damage and repair and genetic alterations.” According to the research, UVB light is more harmful to skin because individuals' bodies are less able to repair DNA damage caused by UVB than UVA light.

According to the report, to reach this conclusion, researchers exposed three sets of cells to UVA light, UVB light and simulated sunlight and compared these cells to an unexposed control group to analyze how well the cells were able to repair the damage. In addition, they analyzed published data on the genetics involved in human skin cancers.

Researchers reportedly found that cells were more easily able to repair the damage caused by the UVA light, which explains why UVA light has been perceived as “safer” than UVB light. Despite this perception, scientists and public health experts caution that UVA light can cause serious damage and lead to skin cancer.

Gerald Weissmann, MD, editor in chief of The FASEB Journal, said in a press statement, “This research article gives us information that could lead to better sunscreens or effective after-sun products. It promises new ways to prevent and perhaps to treat the epidemic of skin cancer brought on by modern life.”

For more information, visit the FASEB Web site at


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