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Understanding Sun Tan Lotions and SPF

Posted February 24, 2008 under Tools of the Trade - No comments

You are on your way to the beach to "work on your tan". You rub in your favorite SPF 15 sun tan lotion all over your skin at 8 am to make sure you don't get skin cancer. Think you are safe? Think again.

Dr. Sinclair's Response

You are on your way to the beach to "work on your tan". You rub in your favorite SPF 15 sun tan lotion all over your skin at 8 am to make sure you don't get skin cancer. Think you are safe? Think again.

The ONLY way to get a tan from sunlight is to DAMAGE your skin. There is no such thing as a "healthy tan". Here is why. The chemical that makes your skin turn brown is called melanin. Melanin is made and stored in special cells in your skin called melanocytes. As your skin is being damaged by the sun, your skin will try to protect itself by releasing the melanin from melanocytes into your skin. The melanin reduces (but does not stop) further damage from the sunlight. Even people with lots of melanin in their skin from birth (Hispanics, Asians, Africans, etc.) can get sun damaged skin and skin cancer, it just takes longer.

Now you might be thinking that if you tan but don't burn you are ok. Sorry, wrong again. By the time you tan, the damage to the DNA in your skin that causes the skin cancer has already occurred. Getting a sunburn means that in addition to damaging your DNA, you have also damaged the skin itself. This damage has to be repaired. Your body sends extra blood to the skin to help with the repair. That is why your skin turns pink or red with too much sun.

The SPF rating is a rough estimate of how much longer it will take you to get a sunburn. For example, if you would normally get a sunburn after being in the sun for 1 hour, then a sun block with an SPF rating of 15 means that it will now take you about 15 hours of sun exposure to get a sunburn. If you would normally burn after being in the sun for 10 minutes, then using a sun block with an SPF rating of 15 would mean that you may not burn until you are in the sun for about 150 minutes (2.5 hours).

Unfortunately, suntan lotions have a few other problems. The lotions rarely stay where you put them. Sweat and water can make the suntan lotions too thin in some areas leaving you with much less protection than you were counting on. Furthermore, the lotions tend to dry out leaving small cracks on the surface of the skin. These small cracks become areas with no protection at all. The cracks in the lotion that are made as the lotion dries are too small to be seen with your eyes, but the sunlight passes right through the cracks into your unprotected skin very easily. Frequent reapplication is necessary to help prevent this problem.

Most sun blocks work by converting some of the UVA and UVB Light into heat. Although the heat won't cause skin cancer, it does cause the skin to sweat. Since the skin is now covered with the sun block, the sweat can't evaporate. The sweat blocks the pores of your skin which then become plugged. The clogged pores can cause your skin to break out.

So what can you do if you have to go outside during daylight hours? There is another kind of sun block that works differently. It uses ground up minerals to reflect the UV light rather than converting the UV light into heat. The sun block is applied as a very fine micronized powder which is highly water resistant. This sun block will retain its ability to protect the skin even after being submerged underwater. It can go directly on bare skin or on top of make up. There are no chemicals (just ground up minerals) so allergic reactions and skin breakouts are very rare. It is safe for children and adults. There is no lotion to dry out so it tends to stay where you put it without cracking. For more information about this sun block, click here.

 

 

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