Understanding SPF

What’s the difference in UVA rays and UVB rays?

UVA rays are the rays that cause premature aging and wrinkling of the skin, think UV-A. “A” is for aging. UVB rays are what cause our skin to burn, think UV-B. “B” is for burn. As of now, the SPF number only reflects the products ability to screen or block UVB rays.

What’s the difference between sunscreen and sunblock?

SPF can be divided into two categories, chemical and physical. Chemical sunscreens are just that: screens. They filter the absorption of UBV rays into the skin but do not completely block them out. Sunblocks, also known as “broad-spectrum” are a physical block and will contain titanium dioxide, zinc oxide, or both. These ingredients are so effective in blocking out the suns rays it’s almost like wearing a long sleeve shirt or a mask on your face. However, sunblocks are typically thicker and should be used with caution on acne prone skin.

What does the SPF number mean?

The SPF on the label ranges from 2 to 60 and refers to the products ability to protect against the suns harmful rays. For example: If you were to use an SPF 10, this would allow you to stay in the sun 10 times longer than you can without sunscreen before burning. Be cautious though, SPF protection does not increase proportionately with the SPF number. SPF 2 with absorb 50% of UV radiation and SPF 15 absorbs 93%. SPF 30 or higher absorbs 97% of the suns harmful rays and is recommended above all others.

When should sun protection be worn?

An SPF of 30 or higher should be applied if sun exposure is longer than 20 minutes at the time. Typically every day errands, even while driving will yield more UV exposure than we think. Even on a cloudy day, 80% of the suns UV rays pass through the clouds. SPF in our cosmetics are usually not strong enough, only around 15SPF most of the time, I recommend that a higher SPF be worn under your make-up.

What is the difference between “water-resistant” and “waterproof”?

The FDA considers a product "water-resistant" if it maintains its SPF level after 40 minutes of water exposure, so if you are using a product that is only water-resistant you should reapply every 40 minutes. A product is considered "waterproof" if it maintains its SPF level after 80 minutes of exposure to water. If you participate in such activities as swimming or water skiing, you may want to choose a waterproof sunscreen.