Basic Overview of Sunscreen

This post has been long promised, but I have to admit that I've been bogged down by exposing myself to way too much information that was much too indepth about sunscreens. But, I have this giant pile of sunscreens that I've promised to review....

So, here we go!

There are 3 main types of sunrays:
• UVA: The longest wavelength, not screened out by ozone, penetrates most deeply into the skin, more responsible for photo-aging
• UVB: Partially blocked by ozone, causes sunburns
• UBC: Completely blocked by ozone and the earth's atmosphere, we are only exposed via artificial sources

Until the last few years most sunscreens have only blocked against UVA rays, but you can see that UVB protection (particularly during the peak times of day 10 am - 2 pm) is very important.

What is SPF?
SPF stands for Sun Protection Factor, and yes, a SPF really is multiplied by how long your skin usually takes to burn. So, if you usually take 10 minutes to burn, with well applied SPF 30 that equals 300 minutes.

I recently found another way to think about it on The Skin Cancer Foundation website:
• SPF 15 blocks 93% of all incoming UVB rays
• SPF 30 blocks 97% of all incoming UVB rays
• SPF 50 blocks 99%of all incoming UVB rays



A few things to think about:
• A SPF 15 should be fine for your normal "out and about" life if you are running errands, going to work, et cetera. If you are spending any significant amount of time outside, you likely need a higher SPF

• A lot of moisturizers and foundations contain SPF 15. I feel very strongly that you need to think about what that product is and how much of it you apply before you decide if that is "enough" SPF for you. If it is foundation and you only apply it in your t-zone, it is not going to protect your cheeks. If it is in your moisturizer which you smear all over your face, neck and chest (hint: you should be doing this already), then you probably are ok.

• If you are prone to sunburns or have a personal/family history of skin cancer, you really should use a higher SPF. During my recent trip to Hawaii I literally had about 7 sunscreens with me. The lowest SPF was about 40. I wore a 70 if I planned to be outside more than 30 minutes at a time. Why? Because I'm the palest person on Earth. And it made a big difference, my only area of sunburn was a small area on my chest that I missed, and it was dark red. That 1 inch area made me very happy that I was so persistent about my sunscreen and reapplication!

• The quoted SPF is based on ideal application. That means at least an ounce of sunscreen for your body, a rule followed pretty much only by me and dermatologists.

• Even if you have followed all of the rules, you need to reapply after 2 hours. Why? Regardless of all the "time" you have for it to work, no sunscreen is meant to work for more than 2 hours. In fact, there is research that shows sunscreen that has been on for too long is counterproductive and (if I'm remembering correctly, I can't find the study right now) actually contributes to skin damage.

• I don't care if you are wearing a water resistant formula, no matter what you need to reapply that sunscreen as soon as you climb out of the pool.

• Don't forget that ideal sunscreen application takes place 30 minutes prior to sun exposure, allowing it to bind with your skin. That means not at the pool side and not while your kids are running around the backyard already. Reapplication there is ok, but the best initial application is inside. I usually do this even before I put on my bathing suit, which helps to prevent missed areas next to the edge, and I can much more easily contort myself in the hotel bathroom than next to the pool.

Moral of the story? Wear a high SPF, apply a lot and reapply often!