Surprising Facts About Sunscreen

Sunscreen is a must.

You need sunscreen: no ifs, ands or buts about it. Melanoma is the deadliest form of skin cancer, and using sunscreen daily is your best defense against it, according to the American Academy of Dermatology. More than 106,000 Americans are expected to be diagnosed with melanoma in 2021.

Even if you think you’re fine because you feel you wear sunscreen pretty often, chances are, you’re not. Here are some surprising facts about sunscreen your dermatologist wishes you knew.

There are different types of sunscreen.

And we don’t just mean different brands. There are different ways that various products work to protect you from the sun’s rays.

“There are chemical sunscreens and physical sunscreens,” you can use to protect your skin, says Dr. Susan Massick, associate professor of dermatology at the Ohio State University Wexner Medical Center in Columbus.

“Physical sunscreens reflect sun rays off the skin and are generally considered the mineral sunscreens — primarily zinc oxide or titanium oxide. Because the UV rays are reflected off the skin, physical sunscreens provide protection from both UVA and UVB wavelengths,” Massick explains. Physical sunscreens tend to be more opaque than their chemical counterparts, but they’re usually gentler on sensitive skin and are more environmentally friendly.

Chemical sunscreens, on the other hand, “absorb and scatter sun rays, with chemicals covering specific UVA and UVB wavelength ranges, so these sunscreens usually contain a mixture of chemicals to provide broad spectrum coverage,” Massick says. She adds that they tend to be simpler to apply because they rub into the skin easier. However, “by nature of being chemically based, these sunscreens can cause skin irritation in sensitive-skinned individuals.”

SPF doesn’t tell the whole story.

Most sunscreens are applied as a lotion, cream or spray, and you’ll often see SPF, or sun protection factor, listed. This label indicates “how long it takes protected skin versus unprotected skin to burn. The higher the SPF number, the more protected the skin is from burning,” Massick says.

Dr. Cheri Frey, a board-certified dermatologist and assistant clinical professor in the department of dermatology at Howard University in Washington, D.C., explains further: “For example, if it normally takes you 10 minutes to develop a sunburn, applying a sunscreen with an SPF of 20 would mean you could be exposed for 20 times as long (200 minutes, or three hours and 20 minutes) before getting a sunburn.”

But SPF only indicates protection against UVB rays — the rays that leave your skin sun burned and itchy. That whole other spectrum of UVA rays, which are much wider and penetrate the skin more deeply, also need to be blocked, says Dr. Joel Cohen of AboutSkin Dermatology and DermSurgery in Greenwood Village and Lone Tree, Colorado. UVA rays are the ones responsible for “causing lines, wrinkles, pigmentation (changes), laxity and skin cancer.”

That’s why you should look for sunscreens labeled as “broad spectrum,” which indicates protection against both types of harmful rays.

Frey says she encourages her patients to use sunscreens that contain zinc oxide or titanium dioxide — physical or mineral sunscreens. These sunscreens offer “the best protection as these ingredients do not absorb UV radiation, but deflect it. They’re generally better tolerated by those with sensitive skin, but they can be too thick and chalky for some patients.”

Frey notes that some newer kinds of sunscreen now also incorporate iron oxide. This mineral is “believed to help protect the skin from visible light, which has been proven to be harmful to our skin with extended exposure.”

More SPF is better — to a point.

While SPF doesn’t tell the whole story, you should be looking to use a higher SPF number rather than a lower one. “Essentially, a sunscreen with a high SPF is expected to provide better protection to our skin,” says Dr. Tanya Nino, a dermatologist and melanoma program director at Providence St. Joseph Hospital-Orange in Orange County, California.

“For daily use, I would recommend SPF 30+, but for more intense sun exposure, I would increase to SPF 50+,” Massick says, because “the higher the SPF, the more effective and protective the sunscreen is.”

However, “once SPF is above 50, there’s not a significant difference between an SPF 70 versus SPF 100,” she adds. But “there can be a noted difference between SPF 15 versus SPF 100.”

You’re probably not using enough.

If you’re doing sunscreen right, you should be using a lot of it — and you need a good bit more than most people realize.

“I tell people that they should apply a marble-sized amount for their face, ears and neck, and a golf ball size (or shot glass size, about 1 to 2 ounces) for the full body. For people who are biking and sweating a lot, I always have them do two applications,” Cohen says.

You’re also probably not reapplying often enough, Nino says. “Many of my patients will say that they got a sunburn even when they applied sunscreen — the issue in these cases is usually failure to reapply. We need to reapply every two hours, or even more frequently when in the water.”

Nino adds that sunscreens are no longer able to claim that they’re “waterproof.” “Now, sunscreen labels will specify if the sunscreen is water resistant for either 40 or 80 minutes.”

When applying, be liberal and “make sure a thin film is covering the exposed areas,” Nino says.

And if you have sunscreen left over from last season, it’s best to pitch it, Massick says. “Sunscreens expire,” so you should buy a new bottle every year.

It’s really easy to miss spots.

It’s a common mistake to miss spots, and that’s where cumulative sun damage can really add up. Massick says you should be sure to cover:

— The face.

— The tops of the ears.

— The back of the neck.

— The throat and chest.

— The hands.

— The tops of the feet.

— All other areas that are exposed to sunshine.

Don’t be afraid to get right up to the hairline too, as that’s a place that’s often missed and can burn easily if you’re not wearing a hat.

And don’t forget your lips. A lip balm that contains titanium dioxide and zinc will help keep your lips protected. Reapply often.

Tattoos aren’t a barrier.

Decorating the body with bright and colorful tattoos is a growing trend, but they don’t offer any protection against the sun’s rays and can actually be damaged by UV rays. Dr. Debra Jaliman, a New York City-based dermatologist and author of “Skin Rules,” says that “if anything, (having a tattoo) will make you more sun-sensitive or offer no protection at all.”

In particular, yellow and red inks contain a chemical called cadmium sulfide, which can cause skin rashes or scaly, flaky skin when it’s allowed to bake in the sun.

Frey recommends using a physical or mineral sunscreen to help protect your tattoo from fading, which can happen over time when it’s exposed to the sun.

Your scalp is vulnerable.

If you part your hair, you’re exposing a sensitive area of skin. If you can’t or choose not to wear a hat, try a scalp sunscreen product. They’re not greasy, and they actually nourish your hair, Jaliman says. If you’re bald or balding, any broad-spectrum spray or cream sunscreen will do.

Scars need sunscreen too.

“Many scars and blemishes will improve on their own with time, but if they’re on sun-exposed areas of skin, they may take longer to resolve,” Frey says.

This is called post-inflammatory pigment change, and it means “protecting scars from the sun is an important step in helping your body to heal faster.”

All scars should be covered with broad-spectrum sunscreen that’s at least SPF 35 at all times, Cohen says. Not only do you run the risk of hyperpigmentation — discoloration or darkening of the skin — but skin cancer is also more likely in those spots because the skin is already damaged.

The sun’s rays don’t discriminate.

Sunscreen should be used by everyone, no matter your race or ethnicity. “Patients with darker skin do have more melanin in their skin cells, which acts as a natural protection to their cells’ DNA,” Nino says. “However, patients of all skin types can get skin cancer and should take measures to avoid ultraviolet radiation damage to their skin cells.”

Even people with very dark skin can burn or develop skin cancer. People of color also tend to be diagnosed later than people with fairer skin, and that can create an opportunity for more negative skin cancer outcomes.

Your dog could be vulnerable too.

Your furry companion is no exception to melanoma risk. In fact, skin cancer is the most commonly diagnosed type of tumor in dogs, reports the American Kennel Club. Though they’re covered in fur, “which give them natural skin protection,” Nino notes, they’re still at risk. Particularly, short-haired dogs, who have less fur blocking their sensitive skin from sun rays than longer-haired breeds, should be careful about too much sun exposure.

“Sparsely covered areas are most susceptible, and like humans, we should try to seek shade for our pet,” Nino says.

You can also buy a specially formulated sunscreen sold at pet supply stores — since human sunscreens are not safe for pets. Pet-approved sunscreen products “generally don’t contain zinc oxide, which can be toxic to dogs,” Frey says.

And Massick adds that dogs can be sensitive to the heat, “so make sure they’re well-hydrated.”

If you discover any unusual lumps or areas of discoloration or if any have changed in size, shape or color, the AKC says it’s time to contact your vet to get it checked out.

Sunscreen is safe.

“Sunscreens are safe to use, and contrary to what you may read, these are not harmful for you with regard to absorption,” Massick says. “Risks of skin cancer and the downsides of a diagnosis of skin cancer, such as melanoma, far outweigh any concerns with regard to sunscreens.”

If you’re still nervous about using any chemicals on the skin, opt for sun-protective bathing suits and clothing, which can be very protective. Such items may be reassuring for parents nervous about exposing their kids to chemicals. Children under 6 months should be kept in the shade.

You can also limit sun exposure and avoid being outdoors between 10 a.m. and 2 p.m., when the sun’s rays are most dangerous.

Lastly, dermatologists agree: Some protection is always better than none.

“I recommend physical/mineral sunscreens over chemical sunscreens because of the broad-spectrum coverage; they’re good for any skin type, including sensitive skin; and they’re environmentally safe for use,” Massick says. But if for whatever reason you just can’t bring yourself to use these sometimes thick and chalky lotions, chemical sunscreens are a good choice too. “Ultimately, it’s what’s easiest for you to use consistently.”

11 surprising facts about sunscreen:

— There are different types of sunscreen.

— SPF doesn’t tell the whole story.

— More SPF is better — to a point.

— You’re probably not using enough.

— It’s really easy to miss spots.

— Tattoos aren’t a barrier.

— The scalp is vulnerable.

— Scars need sunscreen too.

— The sun’s rays don’t discriminate.

— Your dog could be vulnerable too.

— Sunscreen is safe.