So last week we talked about common-sense ways to protect your skin from the sun and we learned that sunscreen is preferably your last line of defense against sun damage.
BUT . . . we all go outside and we all need sunscreen, so let's talk about how to pick the best one for you.
Before we go on, we need to mention that this blog is intended for educational purposes only and cannot nor should not replace the recommendations of your own personal physician. There are many factors that affect which sunscreen you choose, and we are going to try to simplify that process for you.
First things first, sunscreen is meant to protect you from the sun's damaging rays. How does it do that? Well, sunscreen utilizes either chemical blockers (which absorb the damaging rays) OR physical blockers (which reflect the damaging rays), OR a combination of both. These days, most effective sunscreens use a combination.
Chemical blockers that are commonly used include avobenzone, octinoxate, oxybenzone, octisalate, octocrylene, homosalate, and mexoryl.
Zinc dioxide and titanium dioxide are the two physical blockers that are used. Because zinc and titanium do not rub in and instead leave a white, chalky paste sitting on the surface of your skin, often these particles are "micronized" or basically are made super, super tiny so that they do not leave a chalky coating on your skin.
So how do you know whether you want a physical sunscreen, a chemical sunscreen, or both -- and when you are reading the label of ingredients, how do you know if your chosen sunscreen is effective?
There are two things you really need to know regarding the efficacy of your sunscreen -- first is the SPF, or sun protection factor, and second is the spectrum (is it "broad spectrum" or not).
SPF is the numerical rating that describes the relative strength of the sunscreen at blocking UVB rays. Dermatologists generally agree that you want to choose an SPF 30 or higher. SPF DOES NOT imply the duration that a sunscreen will last, but rather the amount of UVB rays that it will block. So choosing a higher SPF DOES NOT mean that you can reapply less frequently. Above SPF 50, the increase in sun protection is small, however for people who have a history of melanoma or are particularly prone to burning, an SPF higher than 50 is often a good choice. At Traceside, our family members are wearing an SPF 70 at the beach.
The SPECTRUM of the sunscreen indicates whether it covers both UVA and UVB rays. As we discussed above, the SPF tells you how well the sunscreen blocks UVB. But what about UVA? The sunscreeen also needs a UVA blocker. The physical blockers will both block UVA. The chemical sunscreen Mexoryl also blocks UVA.
So, in summary, when you are reading the label on a sunscreen you want to choose a sunscreen with:
1. SPF 30 or higher
2. Broad-spectrum (UVA and UVB) coverage
3. to achieve that, you need to either have picked:
* a completely physical sunscreen (zinc and titanium only)
* a chemical sunscreen that contains Mexoryl
* or a chemical sunscreen that ALSO has at least one of the physical blockers
Stay tuned! On our next post we will cover choosing the actual brand and special considerations for people with specific concerns (aka an allergy, sensitive skin, acne-prone skin, etc.).