The start of summer is a great time to reevaluate the sunscreens you have and see what other questions you need answered. Check out our FAQs on sunscreen below.
What’s the most effective way to prevent sun damage to your skin? Staying out of the sun. But avoiding the sun is a horrible way to spend your time, especially when the sun’s rays are partially responsible for lifting your mood.
So, what’s the best thing we have to protect the surface of our skin and the many layers underneath? Sunscreen. We talked with experts and did the research to clear up common sunscreen confusion. From SPF numbers to skin types, here’s every question you have about sunscreen, answered.
How much should I pay attention to SPF?
New York dermatologist Fayne Frey reminds us that “no sunscreen is 100% effective at preventing burning and skin damage.” She also notes that sunscreen “can increase the amount of time you can be outside.” And the amount of time spent outside is somewhat correlated to SPF.
Recent research shows that SPF 100, when compared with SPF 50, makes a real difference in protecting your skin against damage and burns. At a minimum, you’ll want SPF 30.
Frey adds that higher SPFs tend to be stickier, so some people don’t like them as much. But that extra protection is worth it for a beach day, even if you don’t want to opt for it daily.
How does UVA and UVB protection work?
The sun emits different types of light rays, two of which are primarily responsible for damaging your skin: ultraviolet A (UVA) and ultraviolet B (UVB). UVB rays are shorter and can’t penetrate glass, but they’re the ones that cause sunburn. UVA rays, which can get through glass, are more insidious because they affect your skin beneath the surface, even when you can’t feel it burning.
For that reason, you’ll want to make sure your sunscreen says “broad-spectrum,” “UVA/UVB protection,” or “multi-spectrum” on the label. “Broad-spectrum” is the term you’ll most often see in the United States because it’s regulated by the Food and Drug Administration (FDA).
Monique Chheda, a dermatologist in Washington, DC, adds that “usually the two ingredients that provide UVA coverage are avobenzone and zinc oxide, so you definitely want to make sure your sunscreen has one of these.”
What’s the difference between physical and chemical sunscreens?
You’ll hear the terms “physical” (or “mineral”) and “chemical” used to describe sunscreens. These terms refer to the active ingredients used.
Physical (inorganic) sunscreen
Only two inorganic sunscreen ingredients have been approved by the FDA: zinc oxide and titanium dioxide. It’s been thought that inorganic sunscreens create a protective barrier on the surface of your skin that reflects and scatters UV rays away from your body. However, recent research suggests that inorganic sunscreens actually protect skin by absorbing up to 95% of the rays.
Beauty facts! Physical sunscreens typically leave behind a white cast, unless you’re using a tinted product or one that uses nanotechnology to break down particles. Also, while physical sunscreens are branded as “natural,” most are not and need to be processed with synthetic chemicals in order to glide smoothly onto your skin.
Chemical (organic) sunscreen
All active ingredients that aren’t zinc or titanium are considered chemical sunscreens ingredients. Chemical sunscreens absorb into your skin like lotion instead of forming a barrier on top of your skin. These active ingredients “cause a chemical reaction that converts the UV light into heat so that it can’t harm the skin,” explains Chheda.
Chheda encourages her patients to use whichever kind they prefer but cautions that when opting for a purely physical sunscreen, you need to look for one with at least a 10% concentration of zinc oxide to get broad-spectrum coverage.
How often should I apply sunscreen?
“I wear sunscreen 365 days a year,” Frey says. “I brush my teeth in the morning and I put on my sunscreen.” Whether you’re spending the afternoon in the sun or not, make sure you’re applying enough sunscreen for it to actually be effective — most of us don’t. Frey and Chheda both say that the average person in a bathing suit needs a full ounce (or a full shot glass) to cover all exposed areas, including your face, every 2 hours.
If you’re at the beach for the day with your family — say, 6 hours out in the sun — each person needs at least a 3-ounce bottle all to themselves. If you’re not in the water, throw on a shirt and hat and sit in the shade. Every bit of coverage makes a difference. People with dark skin tones and those who tan easily shouldn’t skimp, either.
“Your skin tone shouldn’t decide how much sunscreen you wear. Everyone, regardless of skin color, should apply an adequate amount of sunscreen to ensure full protection,” Chheda advises. Skin cancer survival rates are lower in People of Color, which may be due to inequities in screening care or the beliefTrusted Source that darker skin tones don’t need sunscreen.
Do I really need to wear it if I’ll be indoors most of the day?
Even if you’re not spending the afternoon at the pool, you’re still guaranteed to come into contact with UV rays through the window or by peeking outside. Studies show that daily use of sunscreen can significantly lower your risk of skin cancer and signs of skin aging such as wrinkles, hyperpigmentation, and dark spots.
Reapplication reminders: Always reapply sunscreen. Aim for every 2 hours if you’re outside. The sunscreen you initially put on can move or shift throughout the day. It also takes about 20 minutes for sunscreen to work. If your sunscreen has thicker zinc oxide, you may be able to get away with using less sunscreen, but if you’re unsure, don’t risk it!
Is there a difference between face and body sunscreen?
As far as sun protection goes, according to Frey, the only real difference between face and body sunscreen is the size of the bottle it’s sold in. You don’t need to buy a separate bottle of sunscreen for your face if you don’t want to. There are some great combo products labeled for face and body.
That said, your face is often more sensitive than the rest of your body, so many people prefer a lightweight, nongreasy sunscreen formulated specifically for the face, especially for everyday wear. These are less likely to clog pores, cause breakouts, or irritate skin. You should also avoid using spray sunscreens on your face since it isn’t safe to inhale them. If you’re in a pinch, spray the sunscreen on your hand first and rub it in.
Should kids and babies use different sunscreens than adults?
For babies and kids, as well as those with sensitive skin, dermatologists recommend physical sunscreens since they’re much less likely to cause rashes or other allergic reactions. For little ones, a hypoallergenic sunscreen formulated with zinc oxide.
Should I be worried about harmful ingredients in my sunscreen?
All the dermatologists we spoke to stressed that the active ingredients in sunscreen are vigorously tested for safety by the FDA. But they agree that chemical absorbers are more likely to cause skin irritation, so if you have a skin condition such as eczema or rosacea or you’re prone to allergic reactions, stick with sunscreens that use zinc oxide and titanium dioxide.
Fragrances are also irritating to many people, so a physical sunscreen that’s fragrance-free and hypoallergenic is ideal.
If you have questions about sunscreen safety, Dustin J. Mullens, a dermatologist in Scottsdale, Arizona, recommends checking out the Environmental Working Group’s sunscreen guide, which gives safety ratings to hundreds of sunscreens based on scientific data and literature.
Is my sunscreen killing coral reefs?
In May 2018, Hawaii banned the chemical sunscreen ingredients oxybenzone and octinoxate, which scientists believe contribute to coral reef bleaching. This law took effect in 2021.
Overall, it’s not a bad idea to be proactive and opt for reef-safe sunscreens that don’t include oxybenzone or octinoxate, which gets its UV protection from zinc oxide and titanium dioxide.
Not all mineral sunscreens are totally in the clear, though. Many mineral sunscreens contain microscopic particles of zinc oxide and titanium dioxide, which are called nanoparticles. Recent research suggests that these nanoparticles may also be harmful to coral reefs.
Is stick, spray, or lotion sunscreen better to use?
Some sunscreen is better than no sunscreen at all. But not all sunscreens provide the same amount of protection. Lotion sunscreens typically provide the most coverage because they are easy to pour or squeeze out of a bottle and spread widely on your skin. It’s hard to miss a spot as long as you can reach that spot with your (or someone else’s) hand. They also tend to contain the most protective and least harmful ingredients, such as zinc oxide.
Stick sunscreens aren’t bad, either. But it’s easy to miss a spot because many stick sunscreens are narrow and you have to do a lot more work to get full coverage. They’re convenient to use on your face or smaller exposed areas of skin, but they’re not recommended for use on your entire body if you want convenient, sufficient protection. “Especially for touchups for the face, nose, and cheeks — and don’t forget those ears! They get burned, so a stick would be great for those areas,” says Healthline Medical Reviewer Cynthia Cobb, DNP.
Spray sunscreens generally are not a good idea. Most of the sunscreen that exits the container doesn’t make contact with your skin because it gets scattered into the air from even light airflow or wind. This means that most of your skin won’t get enough protection from UV rays, and you’ll need to reapply it frequently.
Many spray sunscreens also release toxic chemicals and aerosols when they’re used. They can produce nanoparticles that are dangerous to breathe in, and they may also pose a fire hazard if they’re used near open flames.
Does sunscreen expire?
Most sunscreens have an expiration date listed on their containers. The ingredients that make up sunscreen break down over time, so it’s wise not to use a sunscreen past its expiration date to make sure you’re getting enough coverage.
Not all sunscreens have an expiration date. But this doesn’t necessarily mean that they’ll never expire — the FDA allows sunscreen manufacturers to avoid listing an expiration date as long as the product is proven to remain stable for more than 3 years. So if your sunscreen doesn’t include an expiration date, write down the date you bought it and consider discarding it after 3 years so you’re not taking an unnecessary risk with less effective sunscreen.
Does sunscreen limit my vitamin D intake?
It has long been suggested that sunscreen can limit the amount of vitamin D your body takes in from the sun since it largely blocks sunlight from reaching your skin. A 2017 study suggests that sunscreens with an SPF higher than 50 can reduce vitamin D absorbed through the skin by up to 92.5%.
But the study also found that blood levels of vitamin D were reduced by only 7–13%. This indicates that your body likely finds other ways to make up for the vitamin D exposure you’re not getting from sunlight.
The authors of a 2019 review article looked at research published between 1970 and 2017 on sunscreen’s interaction with UV rays. They found that there’s little evidence that sunscreen use limits vitamin D intake — especially because most studies have used artificial UV light that behaves much differently than UV light produced by the sun.
The researchers also warned that concerns about vitamin D intake shouldn’t distract from concerns about skin cancer from direct UV ray exposure. The risk of skin cancer is much higher and more extensively documented than the risk of reduced vitamin D intake.
Other ways to cover up
At the end of the day, “the best sunscreen is the one you’re going to use,” Frey says. And if you’re really looking to cover up, wear a hat, invest in sun-protective clothing, and stay in the shade or indoors — especially during the bright afternoon hours between noon and 4 p.m.
By Rebecca Straus