What is the Difference Between a Sunscreen and a Sunblock?

Memorial Day Weekend is fast approaching and all the pools of the country open officially for the season.  Pool season also calls for consisten protection from the sun.  So, which should we we use for our kids, sunscreen or sunblocks?  Learn the differences right here:

For starters, there are two types of producst that protect us from the sun's damaging UV radiation: chemical and physical products. Sunscreen is classified as chemical, while sunblock is physical.

Suncreens

Sunscreens absorb the ultraviolet radiation. This means that sunscreens reduce the amount of radiation that penetrates the skin. In other words, it does allow UV rays to penetrate but in lesser amounts and strength.  Suncreens are available in creams, lotions and they are inconspicous on the skin. The chemicals that are most often found in sunscreens include PABA, Benzophenones, Cinnamates, Salicylates.  You find them basically everywhere.

Sunblocks 

Sunblocks, on the other hand, are classified as physical. As the name implies, they physically block or reflect both the UVA and UVB radiation from the skin. Sunblocks used to be thick, white, greasy creams made of either titanium oxide and/or zinc oxide, but new technology has created sunblocks with particles so tiny, that the opaque film in no longer noticeable, and now they are avaible in oil-free lotions or tinted concealers (a great alternative to foundation). Sunblocks are usually available at the doctor's, specialty stores or online.

Please note that many products do carry the misleading name "sunblock" but if they do not have as their active ingredients titanium and/or zinc oxide, they are not true sunblocks, only sunscreens. Below are examples of true sunblocks (by Fallene.com):

UVA vs. UVB

Before we go on, let's take a look at the difference between the two types of ultraviolet light, UVA and UVB rays.  UVA is often called the "aging ray" which weakens the immune system of the skin cell, and UVB is called the "burn ray" which causes changes to DNA that can cause abnormal growths in skin cells. To keep them straight of which is which, remember:

UV"A" for "a"ging  and UV"B" for "b"urning

This bring us now to the our next obvious question...

What's an SPF?

Sunblocks and sunscreens are rated with SPF numbers. SPF stands for the "Sun Protection Factor" for UVB rays only - remember B for burning. A sunscreen with a SPF of 15 will delay sunburn from occurring for 15 times (in minutes) longer than normal if using no protection at all. Let's see this exmple:

If it takes someone 30 minutes to sunburn and they applied a sunscreen with an SPF of 15, they would be able to remain in the sun for 450 minutes (15x30). SPF's are rated typically from 1 to 60, although there are some products with an even higher rating. While most suggest an SPF of 15 for everyday use, the activity, time of day, time of year, and the duration should all be considered.

Finally, because this is a post about "differences", let's take a look at the the difference between water-resistant vs. waterproof - ah, did you know there was a difference? Let's take a close look:

The FDA considers a product to be water-resistant if it maintains its SPF rating for at least 40 minutes of water exposure. To secure waterproof status, the FDA states that a product must maintain its SPF rating for more than 80 minutes of exposure.

Now you know important differences to keep in mind all this summer long!

- The Moms Buzz

sources: www.dermastore.com www.melanomafoundation.org