Patients often ask us to explain the differences in sunscreens with higher SPF ratings to those with lower. Many assume the higher the rating the greater protection from the sun and its ultraviolet radiation, exposure to which can lead to skin cancer as well as premature aging and eye damage. The answer, of course, is a little more complicated.
Let’s start with SPF. It stands for Sun Protection Factor and asserts that if you are wearing a sunscreen with an SPF of 15 you can stay in the sun 15 times longer than you could without it. Generally, a 15 SPF sunscreen blocks 93 percent of harmful rays, while a 30 SPF blocks 97 percent and 50 blocks 98 percent. But what’s a safe amount of time to be in the sun unprotected? That, too, is not an easy question to answer, as it depends on the time of day (the hours between 10 a.m. and 2 p.m. are the worst), your skin type, your clothing and the time of year. Suffice it to say, it’s best to limit exposure to direct sunlight.
The dangers of direct and repeated exposure to the sun comes from its ultraviolet radiation, which arrives in the form of waves. Two classifications of those waves, UVA rays and UVB rays, are what we try to block. UVA rays are long wave rays that penetrate deeply into your skin, break down collagen and elastin. UVA rays cause premature aging and can lead to long-lasting damage. UVB rays are short waves, don’t penetrate as deeply, but can burn the outer layers of your skin. Both rays are dangerous and are linked to skin cancer.
Knowing this, it’s critical that you look for sunscreens that you will be willing to wear all the time and those that offer protection from both types of rays. These often are marketed as broad-spectrum sunscreens.
We recommend is that you wear a broad-spectrum sunscreen with a 15-50 SPF and that you wear it on all exposed skin. More important than SPF is that you re-apply the sunscreen regularly, as all sunscreens wear off relatively quickly.
We carry an award-winning sunscreen called Anthelios. This moisturizer and unscreen combo is non-acnegenic with 24-hour hydration. It is a light, oil free formula rich in selenium and is perfect for those who need a long lasting moisturizer with broad spectrum protection. Anthelios is 20 percent off the remainder of June.