Sunday, June 3, 2012
Which Sunscreen Works Best?
With summertime here, let's review the basics about sunscreens. There are so many sunscreen products available that it often feels impossible to choose which type of sunscreen to purchase. I know most kids (& parents) prefer the sprays, because it makes the process so much faster. Unfortunately, I have yet to find a sunscreen with all the ingredients that I look for to ensure the best protection.
Let's start with SPF. What does it mean? Sun Protection Factor is a measure of a sunscreen's ability to protect the wearer against UV radiation from UVB. Note that the sun produces both UVA and UVB, and BOTH cause damage that can lead to skin cancers. Right now, though, the SPF only addresses the UVB protection. So, SPF means that compared to bare skin, the sunscreen keeps you from burning X times longer. If it takes you a half hour to turn red with bare skin, a sunscreen with an SPF of 30 should in theory keep you from burning 30 times longer, which would be 900 minutes- 15 hours. Unfortunately, no sunscreen stays fully effective beyond two hours without re-application. Additionally, sunscreens with an SPF of 15 block roughly 93% of UVB rays, SPF 30 ~ 97%, and SPF 50 is 98%. Therefore, even with perfect application, no sunscreen blocks all UVB rays, and many block no UVA rays.
How much should you use to be effective? You might be surprised to hear that it takes about an OUNCE (picture a shot glass), and that same amount should be reapplied every two hours. This means you will use roughly half of an 8 ounce bottle on ONE PERSON during a full day outdoors!
Which ingredients are important? Most dermatologists recommend combining the physical barrier ingredients that protect against the deep penetrating UVA rays, such as ZINC OXIDE & TITANIUM DIOXIDE (the ones that leave the white residue) along with the chemical barrier agents known to block UVBs, such as PABA, salicylates, cinnamates and benzophenones. Since nearly all sunscreens contain mixes of the chemical barriers, I grab a tube or bottle and scan to be sure it also lists either zinc oxide or titanium dioxide as well. Note that some people are sensitive to PABA or other ingredients, and may do best with purely barrier sunscreens and clothing (such as surf shirts.)
Back to the sprays...for me, there is not an acceptable spray yet, for several reasons. Primarily, there are few with either zinc oxide or titanium dioxide, and those that do are very expensive and have these minerals broken down into "nanoparticles" to allow them to be in a light enough liquid to spray. There is some debate whether these nano-sized minerals can potentially cause cancer, which is of course, the opposite of our intent. Regardless of these issues, probably the biggest issue with sprays is that people use minute portions- picture that less than 10 second total body spray- and so they are not obtaining anywhere near the listed SPF.
What do I buy? Our family typically uses Banana Boat's "Baby" lotion. To it's credit, my kids complain that their skin is "way too white" because I never let them tan. I take that as a measure of success! Probably more importantly, we all use swim shirts, and most of us consistently wear hats and sunglasses.
BOTTOM LINE: Get a sunscreen that contains both chemical and barrier agents (think titanium dioxide) and realize an 8 oz tube should be used up by a family of four in ONE morning OR afternoon since each person needs ONE OZ every TWO HOURS.
PS. NO, I do not have any financial ties to sunscreen makers!