it's not the uvb radiation has linked to cancer. you can see it in these photos. this is the hand of a person with no skin damage, and this is someone with severe photo aging. in a study with 900 patients, those who used sunscreen daily over a 4 1/2 year period were 24% less likely to see these kinds of progressive changes. and doctors say this message will resonate with their patients. >> every patient, we try to tell them to use sunscreen, and believe it or not, just the message of preventing skin cancer doesn't always get through to people. so i'm hoping that maybe vanity will weigh out in this case. >> the rules for sunscreen, she says, are simple. >> you want to look for an spf of about 30. you want it to be broad spectrum, which means it covers uva and uvb types of rays. the most important thing, though, is you want to pick one you will use. >> the sunscreen doesn't have to be expensive either. testing shows that low cost brands can work just as well. i do want to emphasize something, though, in terms of what to look for on that label. you want a sunscreen w

>> have you plenty of uva, uvb radiation.ralians and made a cast of their hand and over 4 1/2 years, if they didn't use sunscreening, when you are bathing, keep re-applying the sunscreenful you prevent the sunburn and you can decrease the risk of aging. there is a dramatic finding. not blinded -- not a perfect study, but very dramatic. i really believe in the result. >> jamie: how's the sunscreen working out for you? >> i don't know how practical it is for me at 5:00 a.m. to put the sunscreen, adding to the shaving cream and the cologne. the way your skin looks fresh and young is number 1, hydration, it's about elastin. that's a rubber tissue under the skin. as long as you are well hydrated. that's a great thing and you want to protect the elastin, that's where the spf comes in. a lot of people think it's during the summertime, but even in the wintertime, you are exposed to t. i will give it a try and get back to you next week. >> i thought you looked younger. congratulations again, doctors. >> congratulations, david. >> than