Turns out the Sunscreen Song was right. But what about SPF?

It's that time of year – vacation season. And since I consider myself somewhat of a season enthusiast, I'm going on vacation. It's not anytime soon, in fact it's over a month away, but as I pulled my fall jacket out of the closet for the first time in six months and headed off to the hospital this morning I began to feel that all too familiar yet pleasantly welcomed compulsion to "pre-prepare" for said vacation. So on my way home from work I stopped at CVS to pick up a few things for my trip. I needed a toothbrush, some floss, and of course sunscreen, because I'm heading south... to a beach.

Now to be clear, I'm not writing this as a public service announcement to advocate the use of sunscreen (we all learned how important that was in 1997 when Baz Luhrmann harmonized the timeless advice of Mary Schmich's Chicago Tribune essay in the sunscreen song. But seriously, wear sunscreen), but rather I want to clear a few things up about the three letters "SPF". What do they mean? And are higher SPF values necessarily better?

Tonight on the way home I stood in front of the sunscreen shelf at CVS for at least 20 minutes reading the ingredients labels of 12 different sunscreens. There was four or five different brands, each with various formulations that were packaged and advertised differently. From "beach-defence" to "water sports" to face – specific formulations to "Kids" to "smooth-feeling”.. Sprays.. Lotions.. “Whipped” (yes, whipped).. etc. Needless to say, I was impressed. Impressed by the multitude of uses we found for a product that's really only designed to do one thing: prevent skin damage from the sun.

There are two important factors to consider when purchasing sunscreen:

1. The sun protection factor (SPF), and 2. Spectrum.

Don't be fooled with fancy labels the next time you stock up. Sunscreen with a SPF of 30 prevents absorption of about 97% of the sun’s harmful UVB rays. For comparison, a SPF of 50 prevents absorption of only 1% more, and SPF values higher than 50 have negligible differences in reducing harmful UV damage. In fact, the FDA recommends that SPF levels be capped at 50 and anything above that simply be labelled as 50+.

So can you tan with sunscreen? The answer is yes. No sunscreen (regardless of the SPF rating) will completely protect you from the effects of UV damage. While the relationship between SPF and UV absorption is not a linear one, the relationship between SPF and the sun's ability to cause skin erythema (or redness) is. That is, SPF 30 is twice as protective as SPF 15. Confusing? It is. While SPF 30 blocks only about 4% more UV absorption than SPF 15, it will take twice as long for your skin to show the effects of sunburn and turn red.

Also, look for sunscreen that says "broad-spectrum" on the label. While most skin damage by the sun's ultraviolet (UV) rays is caused by UVB rays, UVA and UVA1 also contributes. The "broad-spectrum" label ensures the appropriate protection and will reduce your risk of skin cancer and premature skin aging.

Lastly, apply about 20-30 minutes before sun exposure. The sunscreen needs to set on your skin to form its protective barrier. And for those who worry about sunscreen clogging your pores and causing breakouts, many of the new sunscreens are using nanotechnology in their formulations. The molecules that protect your skin no longer are large enough to clog your pores or cause that greasy feeling you might remember from when you're younger.

That's it. I tried not to get too technical with the medical jargon, but we can certainly dive deeper next time. Thank you for your time.

Sources: UpToDate
Images: Pixabay.com