By Brad Yentzer, M.D.
What’s the secret to healthy, younger looking skin?
It comes in a bottle and has a number with the abbreviation SPF behind it.
Good old sunscreen is one of the best ways to avoid skin damage that can lead to wrinkles and other blemishes, all while significantly reducing your risk of skin cancer.
Regardless of the time of year, whether the sun is out or if it’s a cloudy day, if you work in an office or outdoors, I recommend that everyone use sunscreen daily.
Regular use is better than discretionary use because it can prevent the cumulative damage that puts us at the greatest risk of skin cancer. We also create a good habit that can prevent a painful sunburn when we forget to apply or aren’t prepared.
What’s in a number?
The sun protection factor, or SPF, is a measure of the effectiveness of sunscreen. In general, the higher the SPF, the more protection the sunscreen offers against the ultraviolet radiation that causes sunburn, DNA damage, and photoaging.
Many patients ask what is the best level of SPF to use. My answer is the higher the number, the better you will be protected. However, there is not a linear relationship between the numbers and the level of protection. SPF 70 is not twice as effective as SPF 35. A lower SPF (≤15) may block most (about 85-90 percent), but not all the radiation. A higher SPF (≥50) can block nearly all of the radiation, or closer to 98 percent if applied correctly.
Don’t just dab or glisten
If you’re going to take the time to apply sunscreen, make sure you do it right. It does matter how much you use and people tend to use less than they actually need. That’s especially true for people who might not like the greasy feel of sunscreen on their face. But a drop of sunscreen spread thin won’t protect. SPF is rated at 2mg/cm2 – that’s thick!
Some makeup, moisturizers, and lotions do contain a lower SPF sunscreen. While something is always better than nothing, these products aren’t as effective as higher SPF sunscreen.
I recommend searching for a formula that feels right to you. I tell my patients that the best sunscreen is the one that they will actually use on a daily basis.
When applying sunscreen, it should go on thick and white. After about 10 minutes, you can rub it in. Lotions and creams work best because you’ll be able to see if you have enough coverage using this method. They are also more cost effective. Sprays do work, but people usually don’t get enough on. If you use a spray sunscreen, don’t just glisten, make sure you get a good wet stream and apply it out of the wind so it won’t blow away.
Recent changes in Food and Drug Administration labeling requirements for sunscreen now make it clear how long water- and sweat-resistant formulas should last. Look for the time printed on the label as a guide for how long the sunscreen will be water-resistant. A good rule of thumb is always to reapply whenever you towel off. Although there are small differences between sunscreen formulas, the most important words to look for on the label are UVA/UVB or broad spectrum protection.
Sunscreen does not cause cancer!
Several years ago there was a study in rats that raised concerns about a component that is used in sunscreen called oxybenzone, which acts as a chemical filter. The study found that rats fed oxybenzone had a slightly bigger uterus than those that were fed a control diet. This led some to imply that sunscreen applied topically may have adverse hormonal effects and even cause uterine cancer. However, the amount fed to the rats was more than any human would ever apply topically in their lifetime. Subsequent clinical research in humans has shown that there is no evidence of adverse health effects for people, and people should not fear using this chemical in sunscreen products.
The bottom line
Skin cancer can happen at any age, but it happens more as we age. While a sunburn may be painful, the sun’s most dangerous effects accumulate slowly over time. At some point, many people cross a critical threshold where they wear out the warranty on their skin, so to speak, and get skin cancer. Wearing protective clothing, a wide-brim hat and using sunscreen daily can extend that warranty.
