Bob-a-job-alog-a-roonie

My friends have laughed at me over the last few years, whenever I have mentioned the statistic that shows that as sunscreen usage has grown, so has incidences of skin cancer. My best guess was that the artificial substances in the sunscreen were absorbed and cancer resulted. Others guessed as much:

Recently, there has been increased attention to the possibility of adverse health effects associated with the synthetic compounds in most sunscreens. A study published in April 1992, entitled "Could sunscreens increase melanoma risk?" reported that the greatest increase in melanoma has occurred in those regions where sunscreen use is most prevalent. Although one might believe that this effect is due to sunscreens being used more in regions where people are more exposed to UV light, this is not what is claimed by this study: Melanome incidence correlates strongly with the use of chemical sunscreens independently of the actual UV exposure.

Seems I was partially correct, according to a recent New Scientist magazine :(

She and her colleagues exposed human skin samples grown in the lab to UV radiation while they were covered with three common UV filters found in sunscreens: benzophenone-3, octocrylene and octylmethoxycinnamate. After just 1 hour, they found each compound had sunk into the skin, meaning its protective effect was greatly reduced. Worse, Hanson's team found that the samples contained more reactive oxygen species (ROS) than skin exposed to UV with no sunscreen on it. ROS are free radicals that can damage skin cells and increase the risk of skin cancer (Free Radical Biology and Medicine DOI: 10.1016/j.freeradbiomed.2006.06.011).

So, sunscreen increases the chances of skin cancer, unless you keep re-applying it all day. Best just cover up or stay in.