At this time of year, I often get a lot of questions about sunscreen. I believe that there’s a lot of confusion as to what qualifies a sunscreen as the “right” sunscreen and when and how it should be applied. To complicate matters the Internet is filled with differing opinions as to how healthy sunscreen is overall. To alleviate a bit of this confusion, I’ve come up with a list of common questions I receive and take a little time to dispel some of the more common misunderstandings about sunscreen and its use.
I use make-up with an SPF in it, am I protected?
This question I get a lot. While it’s great to buy and use make-up with added SPF, it shouldn’t be the only sunscreen you use. Regardless of whether it’s sunny or cloudy outside, or you spend most of your day inside, you need protections from a broad-spectrum sunscreen with an SPF 30. Broad-spectrum sunscreens protect against UVA and UVB rays. According to the FDA guidelines, the appropriate sunscreen should have the following:
- Products that pass the stringent FDA guidelines will be labeled “broad spectrum” followed by an SPF number. To receive this label, the product must pass a test to prove they protect against both UVA and UVB rays.
- No product can claim to offer around-the-clock protection. Sunscreens must have a warning that urges users to reapply every 2 hours or after swimming.
- Sunscreens can no longer use terms like ‘sweat proof’ ‘water proof’ and ‘sun block.’ Products that pass this waterproof “test” must be labeled ‘water-resistant’ up to 40 to 80 minutes.
- Products with an SPF lower than 14 or that are not broad-spectrum must carry a warning that reads ‘this product has been shown only to help prevent sunburn not skin cancer or early skin aging.’
It’s okay that I don’t use sunscreen on cold, cloudy days or on days when I’m inside all day, right?
Not exactly. You’re just not as protected as you should be. Forty percent of the sun’s ultraviolet radiation reaches the earth on a completely cloudy day. A friend of mine got his most serious sunburn on a cloudy day at the beach. If you plan on being outdoors, even when it’s cloudy you should be using sunscreen. If you should accidentally forget the sunscreen, cover up with clothing. T-shirts and long-sleeve shirts, at the very least, will provide an SPF protection of at least 7 or 8. Wear a wide-brimmed hat and also sunglasses with UV-blocking properties.
Research has proven that skin exposed to sun shining through window glass, even in the office, or through the driver’s side or the passenger’s side of a car can lead to significant skin damage over time. Car windshields are specifically treated to block UVA and UVB rays, and even glass blocks UVB rays effectively, but not UVA. The side and rear windows of a vehicle, and even office windows, allow UVA rays to penetrate. This is why it’s so important to be sure your sunscreen is labeled broad-spectrum to protect you from both UVA and UVB rays.
Can wearing sunscreen cause Vitamin D deficiency?
Even with sunscreen on, you’ll still receive enough of this nutrient from the sun. While it can be more difficult for our bodies to make Vitamin D as we age, or receive it during the winter months, you can receive the benefits of this nutrient through a supplement or fortified foods, like salmon, eggs, enriched milk and orange juice. According to the Institute of Medicine, adults need 600 IUs of Vitamin D a day. Check with your health professional before taking a supplement.
Is last year’s bottle of sunscreen safe to use?
While most sunscreens have a shelf life of two years, I tell my patients if you have sunscreen left over from last year, than you’re not using correctly. For full protection, you need to apply 1 ounce or a shot-glass worth of sunscreen. Don’t forget the tips of your ears, the back of the neck and hands, and if you’re wearing sandals the tops of your feet.
A Higher SPF means the sunscreen protection is better, right?

SPF 30 or SPF 50?
It would stand to reason that if you have a sun protection factor of 60 it would be twice as effective at protecting you than an SPF of 30, but it’s not really how it works. It’s actually just a few more percentage points more effective. Here’s the breakdown. An SPF of 15 actually filters 93 percent of the sun’s rays and an SPF of 30 filters 97 percent. For another way to look at the numbers, let’s say for example, it takes 20 minutes for your unprotected skin to start turning red. With an SPF 15 sunscreen, it should prevent your skin from turning red 15 times longer – or about five hours.
But what’s most important to remember about sun protection is that no sunscreen, regardless of the SPF factor, will fully protect your skin for longer than two hours. While the “redness” of our skin, or the lack of it, may be an indication of how well our sunscreen is working, it tells us very little about UVA damage. UVA damage is what causes wrinkles, sun spots and skin cancer. In the long run, reapplication of sunscreen, whether its SPF 30 or SPF 50, is the best defense against skin cancer and damaging rays year round.










