NEWSLETTER

Summer 2008

The Truth about Sunscreens (and Sun Blocks)

There is much confusion about sun protection and especially about sunscreen use. I am often asked by my patients which sunscreen to use and if it matters how high a number the tube has on it. Let me summarize the basics about this issue.

There is no real disagreement about whether sun exposure can lead to skin cancer in certain individuals and that sunburns are even more dangerous. Many people will never get a skin cancer due to genetic reasons ( just like some people can smoke cigarettes all their life and not get lung cancer ) but for the majority of us it is likely that we will get skin cancer or lung cancer unless we are careful to avoid these carcinogenic exposures.

The SPF numbers on the sunscreen labels start at the number 2 and go up from there. They represent a sunscreen's ability to protect our skin from UVB sun rays. Theoretically, using a 15 sunscreen will allow you to be in the sun 15 times longer than if you used no sunscreen at all, before you would then get a sunburn. To answer my patients' question as to whether 15, 30 or higher numbers make a difference:

An SPF sunscreen of 15 filters out about 93 percent of the UVB rays, a number 30 filters out about 97 percent and a 50 number filters out about 98 percent. So you can see why some feel anything higher than a 15 sunscreen is not worth it. Since these sunscreens are only effective if they are put on liberally and reapplied every 2 hours and there are still other UV rays that reach the skin, especially UVA, I recommend my patients use the highest number possible for their sunscreen.

In the last few years it has become apparent that skin cancers are still on the rise, especially malignant melanoma, despite widespread sunscreen use. Some doctors believed that the sunscreens themselves were to blame, but a lot of recent research has put that concern to rest. What is now thought to have happened is that we were protecting our patients mostly from UVB rays with standard sunscreens and UVA was being ignored. UVA rays are now believed to be responsible for more skin cancer causation than UVB. So, we have had less sun burning but more UVA exposure. Since this was discovered, all major sunscreen companies have attempted to include "UVA blocking agents" (broad spectrum agents) in their products. It is not hard now to find many products labeled with these UVA blocking agents in them.

The FDA has recently decided to change the way companies can advertise their sunscreen products to better educate the customer what they are getting. SPF numbers will be more regulated, UVA and UVB protection will be emphasized and the word "Sun block" will be eliminated.

Lastly, it is now recommended for people very sensitive to the sun and with a family history of skin cancer to use sun protective clothing as well as sunscreen whenever they are to be out in the direct sun.

Return to Summer 2008 Newsletter