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SPF – What does it really mean?

May 27, 2010

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So you think you know what SPF is? I did, until I read an article that told me differently. So I started looking into it to see what the real story is.

You’d think that with a name like “Sun Protection Factor“, it would mean how much you’re protected from the sun, right? Well, only 1/2 right. SPF only measures the amount of UVB rays absorbed by the skin, NOT the UVA rays! The truth is that you need full spectrum protection, protection from both UVA and UVA.

What’s the difference between UVA and UVB you ask? UVB rays are short waves and can only be absorbed into the outermost layers of the skin. These are the rays that cause sunburn. For a long time, these were the rays that were thought to cause most skin cancers. That’s why years ago, the SPF ratings were created to measure how much UVB was blocked or absorbed by sun products. Whoa! What do you mean absorbed?! We’ll get to that later.

UVA rays, on the other hand, are long waves that can actually penetrate deep into the skin. These rays can permanently damage the lowest layers of the skin, causing signs of aging like wrinkling and “leathering”. Some of this damage can be reversed with deep repair products such as BC’s Regeneration line, but some damage can be permanent. We’ve recently come to find out that UVA can also cause some cancers.

Back to that comment about UVA/UVB “absorption”. Do you know the difference between sunscreen and sunblock? If you do, then you were way ahead of me before I started my research. Sunscreens are products that absorb the rays that enter your skin. That’s right, absorb! What I’d like to know is where does it go after it’s absorbed into your skin? It doesn’t take a genius to know it has to go somewhere. Until recently, sunscreens were only effective against UVB rays, now there are a few ingredients that are effective against UVA as well. Sunscreens take at least 20 minutes to start working, so don’t wait until you’re walking out the door to put it on. Most sunscreens also need to be reapplied after several hours of exposure to sunlight.

Sunblocks, on the other hand, are physical barriers to UVA and UVB. They actually reflect the rays from ever getting to your skin. I’m not sure about you, but this is the method I prefer. Don’t want those nasty rays getting anywhere near my skin 😉 Sunblocks don’t have to be applied in advance, so this is the one you should use if you’re not great at planning ahead (like me). They also don’t have to be reapplied as often as sunscreens.

So what do those goofy numbers like SPF20 mean? It was initially meant to show how many times longer you could stay out in the sun before burning. For example, if you could normally stay out 15 minutes, then SPF20 would theoretically mean you could stay out 5 hours. However, in light of the fact that those ratings only apply to UVB, they really don’t mean much anymore. What we need is a whole new rating system. What I thought was interesting though, is the percentage of UVB that SPF blocks (or absorbs):

  • SPF 15 blocks 94%
  • SPF 20 blocks 96%
  • SPF 30 blocks 97%
  • SPF 45 and above blocks 98% – 98.5%

Notice that minor difference when you get above SPF15? In a host of other countries, manufacturers are not allowed to show any rating above 30 – 45, since this is misleading to the public. Some people think SPF60 is twice the protection as SPF30, when it’s actually only 1.5% more effective. A lot of researchers believe that you really don’t need anything over SPF20.

The main thing is to make sure you look at the labels and make sure you’re getting both UVA and UVB protection. Make sure you’re using at least SPF15 (I use SPF20), and reapply every couple of hours. This is especially important on your face, even when it’s cloudy out. It’s also important to use a product that has antioxidants in it (see my previous posts), to help combat free radicals and prevent sun damage from the rays that do get through. Personally, I use BC’s Cell Block C which has both.

If you have any questions, post them here or on my Facebook fan page: http://www.facebook.com/pmicreations

Hope everyone has a great Memorial Day weekend, and remember to wear sunblock!!

Christine

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7 Comments leave one →
  1. June 4, 2010 10:53 am

    My sister showed me this site after my post: http://www.ewg.org/2010sunscreen/full-report/epidemiology-studies-of-sunsreens-efficacy-for-cancer-protection/

    Interesting reading about skin cancers and the lack of information about sunscreens/sunblocks.

  2. June 2, 2010 4:29 pm

    Just in time for the Summer Sale, Cell Block C with antioxidants and sunblock in on sale in June!

Trackbacks

  1. Cell Block C AM SPF 20 Review | Mobile Spa Squad
  2. Expiration Dates, Is Your Makeup Safe? « Primitive Moon Health & Lifestyle Blog
  3. Cell Block C AM SPF 20 Review « Primitive Moon Health & Lifestyle Blog

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