The Ultimate Sunscreen Guide

It is a ritual most people need to make a part of their daily routine, especially if you live in warmer climates or spend a lot of time outdoors (time in the car counts). Yes, the sun’s warm rays can be restorative and comforting, but overexposure to ultraviolet light (both UVA and UVB rays) can lead to skin cancer and premature aging.

Get answers to common questions about this healthcare essential from our Canyon Ranch experts.

Only Some People Need to Use Sunscreen…Right?

No—everyone needs sun protection, no exceptions. This includes people who have dark skin and who have no family history of skin cancer. Remember, you can’t feel or see a burn until after the fact, and skin can be damaged even without a visible burn.

Do All Sunscreens Reduce My Risk of Skin Cancer?

No. When it comes to protecting your skin, using any sunscreen is better than nothing at all. However, not all sunscreens offer the same benefits. That is why the Food and Drug Administration (FDA) has ruled that a sunscreen’s label can only state that it helps prevent sunburn and reduces the risk of skin cancer (and early skin aging) if it has an SPF of 15 or higher and is broad spectrum, meaning it blocks both UVA and UVB light. Remember, these benefits only come with proper, consistent use, so be sure to read the instructions on any sunscreen before you apply.

But Isn’t It True That Using a Higher Spf Sunscreen Gives Me Better Protection?

Yes and no. An SPF 15 sunscreen filters about 93 percent of rays, whereas an SPF 30 filters 97 percent and an SPF 50 filters up to 98 percent. These small differences can mean a lot, particularly if you’re prone to burns. The American Academy of Dermatology (AAD) recommends using a sunscreen with an SPF of 30 or higher, but don’t bother searching for SPF 100. The FDA has no sufficient data to show that an SPF higher than 50 provides greater protection, which is why sunscreen labels may no longer tout a specific SPF above that number. Unfortunately, no product can actually shield you from 100 percent of the sun’s rays—which is why the use of the term “sunblock” is also prohibited.

When Do I Need to Use Sunscreen?

Every day. UV rays penetrate cloud cover and most glass, so it makes sense to wear sunscreen even if it’s overcast or cool, or if you spend a lot of time driving or indoors near a window or under a skylight. Sunscreen also works best when it has had time to be absorbed. Apply it 15 minutes before going outdoors, and don’t forget to take it with you so you can reapply as needed (every two hours, or sooner if you’ve been sweating or swimming).

How Much Sunscreen Do I Need to Use?

Most labels will instruct you to “generously” or “liberally” apply your sunscreen, which can mean different things to different people. A good rule of thumb, according to the AAD, is to use one ounce of sunscreen (enough to fill a shot glass) each application, though you may need more or less depending on your size. It can be tough to gauge how much of a spray sunscreen you’ve used, but aim to cover every square inch of exposed skin, steering clear of your eyes. Try spraying the product directly into your hands and then rubbing it on your skin; it’s also a good way to avoid inhaling the spray by accident. Don’t forget about your lips, ears, scalp, neck, hands and feet—they’re susceptible to the sun, too!

Doesn’t Waterproof Sunscreen Stay Put When I Swim or Sweat?

There is no sunscreen formula that is 100 percent “waterproof” or “sweat-proof,” and these claims are no longer permitted on sunscreen labels. Sunscreens can be water-resistant, however, meaning they retain their SPF for 40 to 80 minutes after exposure to water. But that doesn’t mean you can slather it on in the morning and spend the rest of your day in and out of the pool without needing to reapply. Water-resistant and sweat-resistant sunscreen labels indicate how long the lotion’s protection lasts, so be sure to reapply according to the instructions. (Get out of the water, take a 15-minute reapplication break and get back in, if you have to.) You should also reapply after toweling off.

Do I Really Need to Pay Attention to the Expiration Date on My Sunscreen?

Yes. The active ingredients in sunscreen break down over time, and can become less effective at keeping you protected. Always check the expiration date on your sunscreen before using, and toss any bottle that is past its prime. Per the FDA, any sunscreen that does not have an expiration date stamped on its packaging has a shelf life of no more than three years, but keep in mind that higher temperatures can also cause sunscreen to break down. So, if you’ve been toting the same bottle back and forth to the beach for the past two summers, it’s probably a good idea to get a new one.

I’ve Heard That Certain Ingredients in Sunscreen Can Be Harmful. Should I Worry About Using Them?

There are two different types of sunscreen—physical sunscreens, which sit on top of the skin (think of the white zinc oxide lifeguards often use on their noses), and chemical sunscreens, which are absorbed into the skin. There has been talk that some chemical sunscreen ingredients may be dangerous—specifically that oxybenzone can interfere with hormone levels, and that retinyl palmitate may generate free radicals, contributing to cancer. According to the Skin Cancer Foundation, there is no scientific evidence that this is true for humans, and the ingredients remain approved by the FDA for the same reason. You can also opt for physical sunscreens and other barriers such as long-sleeve shirts, wide-brim hats and umbrellas.

What About Vitamin D? I’ve Heard That the Best Way to Get It Is to Soak in Some Sun, but Won’t Those Rays Do More Harm Than Good?

It depends. Vitamin D plays an important role, helping to stave off osteoporosis, heart disease and certain cancers. And it’s best to get your fill from diet (eggs, fatty fish, fortified dairy products), supplements (if recommended by your doctor) and sun exposure. So, many experts recommend that people—especially those more prone to vitamin D deficiency, such as older adults—spend 10 to 15 minutes in the sun without sunscreen two to three times weekly to take advantage of the body’s own ability to produce the vitamin when UVB light hit the skin. But for people with very fair skin or a history of skin cancer, even brief unprotected periods in the sun can be harmful. Talk to your doctor about the best way for you to get the right amount of daily vitamin D.

The Environmental Working Groups Guide to Sunscreens may be useful to you as you choose among the myriad products available today.