The Science of Beauty: The Complete Guide to Sunscreen

Julie Ricevuto
·16 mins read

Join the editors of Allure as we ask the tough questions at the intersection of science and beauty, and get straight answers from dermatologists, cosmetic chemists, and at least one expert on climate change (we said the questions were tough). It's all going down on The Science of Beauty, a new podcast hosted by editor in chief Michelle Lee and executive beauty director Jenny Bailly. (Available on Apple Podcasts, Spotify, or wherever you listen to podcasts.) This episode made possible by Olay.

But because we can only get so nerdy over the airwaves, here we take the conversation one step further by breaking down our findings and adding more crucial facts — so you too can become an expert. It's fitting, then, that sunscreen — the most essential skin-care product there is — is our first topic.

Slathering on sunscreen every morning is a lot like putting on a face covering before heading outside during a global pandemic — necessary, yet still a bit of a learning curve. But since science has made it crystal clear that these are both non-negotiable steps in our days, we need to figure it out. Just as wearing a face covering helps protect against a deadly virus, sunscreen can literally save lives, too.

Here’s proof: All it takes is one blistering sunburn in childhood or adolescence to more than double a person's chances of developing melanoma in their lifetime. And since vanity can also be a powerful source of motivation we’ve got you covered there, too. Research has found that sun exposure is responsible for 80 to 90 percent of the visible signs of skin aging, like fine lines, discoloration, and laxity.

Obviously, sunscreen is vital, but there’s still a lot of confusion surrounding the stuff. The safety of sunscreen ingredients has come under scrutiny recently, and a lot of the marketing terms you see slapped on pretty packaging can read like a foreign language. So, in an effort to clear up some of that confusion, we chose this topic to be the first issue addressed in The Science of Beauty podcast. Here, we break down sunscreen's history, the key terms everyone should know, and share expert-approved product picks.

The History of Sunscreen

While sunscreen has only existed for a little less than a century, sun protection has been around for much longer than that. In many parts of the world, having pale skin was seen as a status symbol and, of course, of being white or having proximity to whiteness. So, thousands of years ago, Ancient Egyptians smeared products like jasmine and rice bran onto their skin to prevent it from darkening. Even wilder: In the 16th century, some European women wore face masks — called visards — that consisted of an outer layer of black velvet, followed by layers of pressed paper, and an inner lining of silk. It extended out to accommodate the nose, with small holes for the eyes and an opening for the mouth. The visard was apparently a high fashion item among the wealthy during its peak, but the trend fell out of style by about the 18th century.

Eventually, the founder of L'Oréal, Eugène Schueller, invented the first sunscreen — called Ambre Solaire — in 1935. In the late 1930s, a product called Glacier Cream — which had a more-refined formula — was invented by a chemistry student who experienced a sunburn (it wasn't until 1946 that Glacier Cream reached the market). The 1940s brought about a new era in sun care with the introduction of Coppertone, which came complete with now-iconic ads and jingles. At this time, the purpose of sun protection was still to safely tan, not to fully block out the UV rays of the sun.

Thankfully, products with super-high SPFs were finally released in the 2000s (more on why that's important in a minute). And today, the importance of sunscreen is more widely known due to the magnitude of studies on the relationship between sun exposure and skin cancer.

Sun Protection and the Environment

Perhaps now more than ever before, wearing sunscreen is critical. While there are many reasons for this, one is that our ozone layer has been depleted, leaving us less protected from the sun's harmful rays. Shyla Raghav, the vice president of climate change at the nonprofit organization Conservation International, explains that the ozone layer provides critical protection from the sun, even acting as a natural sunscreen.

As it thins, humans are exposed to higher levels of ultraviolet rays. (We definitely don't have the natural sun protection that people had in the 1940s or '50s.) This, combined with the fact that warmer weather in many places has driven people to spend more time outside, says Raghav, can be linked to an increase in skin cancer rates over the years.

Since the ozone layer doesn't offer as much protection, it's become easier for us to experience serious skin damage. According to Caroline Robinson, a board-certified dermatologist in Chicago, it can take as little as a few minutes of unprotected sun exposure to do some serious damage to our actual DNA (UVB rays can travel through the epidermis into cells, and actually cause breaks in our DNA strands). Even though our skin cell repair mechanisms are constantly working to repair DNA damage, it's really hard for the skin's repair system to keep up with the constant DNA damage that occurs when consistently exposed to the sun. That means that those cells can become abnormal over time, and eventually become cancerous.

Although, as the COVID-19 pandemic continues, Raghav believes it's possible that this skin damage has decreased for humans a bit. "Staying at home has meant less sun exposure and possibly less reef-damaging sunscreen making its way to corals and marine life," she says. "There certainly have been temporary benefits due to the COVID-19 [lockdowns], but these effects are just that — temporary."

Raghav concludes that the COVID-19 quarantines have prompted a deeper awareness of our relationship to the planet and a recognition that human and planetary health are linked. "From this place of recognition, I think we can all be more receptive to holding our corporate and government leaders accountable to build back better and invest in solutions to both the climate crisis and the need to stop producing ozone-depleting substances," she says.

Mineral vs. Chemical Sunscreen: What’s the Difference?

There are two types of sunscreens available: mineral and chemical. Chemical sunscreens protect from UV rays by absorbing them with chemical ingredients, such as octocrylene or avobenzone, and turning them into heat. Mineral sunscreens achieve their SPF with physical blockers, like titanium dioxide and zinc oxide. They form a physical barrier between UV rays and the skin. While many people may be under the impression that mineral sunscreens are "natural," they are not. "Both chemical and mineral sunscreens are made in a lab," confirms Robinson.

Chemical sunscreens typically have a thinner consistency and tend to blend in more easily than their mineral counterparts. However, these ingredients can cause irritation for many people with sensitive skin.

But for those who prefer mineral sunscreens because they sit on top of the skin and are less likely to be absorbed or cause irritation, there's a different set of complaints. Many say that mineral sunscreens feel thicker, tend to rub off more quickly, and can look a bit chalky. Although, formulas are improving. "The sunscreens back in the day had large zinc particles in them," says Robinson. "And that created a lot of the chalkiness and a lot of the heaviness and greasiness that we associate with sunscreens of the past."

Today, new innovations have led to an improvement in the size of the particles used in mineral sunscreens. They've become smaller and use different shapes to bounce the light off skin in a more cosmetically appealing way.

Is It Safe to Wear Sunscreen?

Everyone got very nervous about 'chemical' sunscreens back in February 2019, when the U.S. Food and Drug Administration (FDA) announced that it was going to be reevaluating the safety of all of the non-mineral sunscreen ingredients, explained Jenny Bailly, executive beauty director, during episode one.

A new study conducted by scientists from the FDA had examined six active ingredients (avobenzone, oxybenzone, octocrylene, homosalate, octisalate, and octinoxate) commonly found in sunscreen and found that after a single use, all six ingredients had been absorbed into the bloodstream. “Sunscreen is coursing through your veins!” was the general tenor of many of the headlines that ran at the time. But the mere fact that a chemical shows up in your blood (or urine) does not mean it’s causing any harm to your body. Additional data is needed to understand the long-term effects of sunscreen absorption — many of the chemicals that we encounter every day are absorbed by our bodies, but absorption does not equal risk. Experts — Robinson included — stress that consumers should still use sunscreen regularly. Additional data is definitely not needed to establish that sun exposure is a cause of skin cancer. "For my patients who are very, very concerned about this, I often have a conversation [about it] because the tendency is to stop [using] sunscreen altogether — and that's the worst thing," she says.

Particularly frustrating for Robinson is that the fear of chemicals in sunscreen has created an additional barrier in getting patients with darker skin tones to use SPF. Many of her patients still believe the myth that people with darker skin tones don't need daily sun protection—and concerns about the chemical sunscreens that generally work best on their skin aren’t helping the problem. (Only about 11 percent of non-Hispanic Black adults and about 25 percent of Hispanic adults regularly use sunscreen, compared with 40 percent of non-Hispanic white adults, according to a survey conducted by the Centers for Disease Control and Prevention.)

While people with deeper skin tones may not be more susceptible to skin cancer, the American Academy of Dermatology (AAD) says that when skin cancer develops in people of color, it's often not diagnosed until the late stages. This makes the treatment difficult and the cancer can even be deadly. "I've had patients [with a darker skin tone] who didn't know they had sunburn because they didn't recognize it," warns Robinson. "They thought it was a rash on their skin."

How is SPF Measured?

Once you've chosen either the mineral or chemical sunscreen route, you can consider a few other key terms when picking a specific product. The most important thing to look at on your sunscreen bottle is the SPF — or sun protection factor — which specifically refers to protection from UVB rays. The number next to it is a measure of how well the product will protect the skin against sunburn — as the SPF value increases, so does sunburn protection.

One important thing to note: the SPF number only refers to how long it would take the sun's UV radiation to burn your skin when using the product as directed, versus the amount of time it would take to burn without sunscreen. So, with SPF 30, it would theoretically take you 30 times longer to burn than if you weren't wearing sunscreen. (Theoretical is the keyword here — this doesn't account for your unique complexion or how thoroughly you applied your sunscreen.)

However, SPF is not a measure of UVA protection, which brings us to our next important term to look for: broad-spectrum.

Broad-spectrum means the sunscreen offers protection from both UVB rays, which burn skin, and UVA rays, which travel deeper and cause collagen to break down. UVA rays are the rays that visibly age us, explains Robinson.

Protection against UVA radiation is more important (and complex!) than you might think. UVA radiation causes something called oxidative stress, meaning the oxygen molecules in our skin become really unstable and create something called a free radical. Free radicals cause the breakdown of collagen and elastin, which as we already know, leads to the development of fine lines and wrinkles.

So, not only do we need to wear a broad-spectrum sunscreen to prevent UVA radiation from damaging the skin, but Robinson recommends layering an antioxidant product underneath our SPF to absorb those free radicals and help neutralize them before they can create any damage. (Her personal pick is Revision C+ Correcting Complex 30%.)

How to Choose a Sunscreen

Now that we've broken down all the science of sunscreen, it's time to find your perfect match. The best sunscreen for you depends on many factors, but most importantly, on your skin tone and type, and your preferred product format.

1. Skin Tone

A lot of options on the market are not formulated with darker complexions in mind (again, all skin tones should be wearing SPF daily), so they end up looking chalky. Chemical sunscreens tend to look less chalky, but they can be irritating, which brings many people back to mineral sunscreen. Luckily, mineral sunscreens are improving. A good option is the Drunk Elephant Umbra Sheer Physical Daily Defense Broad Spectrum Sunscreen SPF 30, which — while zinc oxide-based — still blends to a sheer finish on all skin tones due to its lightweight texture.

Pro tip: Robinson recommends adding a drop of foundation to your favorite sunscreen in order to get a less chalky finish and create a tint that matches your skin tone.

2. Skin Type

For those with oily skin, opt for an oil-free formula, like our 2020 Best of Beauty winner, La Roche-Posay Anthelios Anti-Shine SPF 60+ Dry Touch Gel-Cream. Dry skin will benefit from a more hydrating formula, like the Olay Regenerist Whip Active Moisturizer with Sunscreen SPF 40, while those with sensitive skin should consider a gentle product like Aveeno Positively Mineral Sensitive Skin Sunscreen Stick SPF 50, which is fragrance-free, paraben-free, and phthalate-free.

La Roche-Posay Anthelios Anti-Shine SPF 60+ Dry Touch Gel-Cream

$20.00,

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Olay Regenerist Whip SPF 40

$39.00,

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Aveeno Sensitive Skin Sunscreen Stick SPF 50

$12.00,

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3. Formula Type

Finally, don't forget to consider formula types when shopping for an SPF. Traditional lotions tend to be thicker than gels and mousses, but may be easier to see where you're applying. Sprays are easy to use, very lightweight, and dry quickly, however, it can be hard to see where you've already applied and can cause you to leave an area unprotected. For a better chance of adequate coverage, pros suggest patting these formulas into the skin after you've sprayed.

Also, it's important to note that sprays can be dangerous if you accidentally breathe them in. Some sunscreen ingredients can be lung irritants, specifically titanium dioxide, which has been classified by the International Agency for Research on Cancer as "possibly carcinogenic to humans," after scientists found a link that showed increased lung tumors in rats exposed to the ingredient. However, research on humans has not reported an association between inhaling the ingredient and an increased risk of cancer. As previously reported by Allure, the FDA has proposed to allow sprays, with one condition: their particles must be large enough that you can't breathe them deep into the lungs.

The last sunscreen format, powder, contains the same active ingredients as lotions or sprays (titanium dioxide and zinc oxide), just in powder form. According to Robinson, powder sunscreens are a great option for reapplying throughout the day. However, it's best to use them to touch-up — not as your main source of SPF. Here's why: It would take quite a lot of powder to get the full SPF, but people typically only apply a small bit of powder. If your powdered sunscreen is labeled SPF 25, but you only blot on a swipe of powder, you're not getting anywhere close to SPF 25 protection. This is something to keep in mind for any sunscreen format — the FDA uses a thick layer of sunscreen in the tests they use to determine SPF values, and it's highly unlikely that you are using that much at home. Always apply as liberally as possible, while accepting that it's unlikely you're achieving the full SPF number on the bottle (a reason you might want to consider going higher).

Similarly, Robinson urges her patients not to rely on makeup products that contain SPF as their sole form of protection. We’re usually (hopefully) not wearing a thick layer of it, plus "we typically are not applying our makeup in all of the areas that we need some protection, like the back of our ears or the back of our neck," she says.

Our Hosts' Sunscreen Picks

Michelle's Current Favorites

She alternates the tinted lightweight formula of EltaMD and the creamy texture of Olay Regenerist throughout the day. Sometimes she layers the ReVive under the EltaMD because it smells really nice and has a refreshing effect. And if she's going to the beach, she uses Supergoop, because it gives her a very dewy glow, which is a bit much for office settings or video conferencing.

EltaMD UV Daily Tinted Broad-Spectrum SPF 40

$32.00,

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Olay Regenerist Whip SPF 40

$39.00,

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Revive Perfectif Even Skin Tone Cream-Dark Spot Corrector SPF 30

$275.00,

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Supergoop Glow Stick Sunscreen SPF 50

$25.00,

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Jenny's Current Favorites

She's currently very into Rihanna's Fenty Skin, which has a slight pink tint and "looks beautiful on every skin tone." She likes Isdin for everyday use because it's lightweight and layers well with makeup. And she uses La Roche Posay, which dries very matte, to avoid breakouts from sunscreen.

Fenty Skin Hydra Vizor Invisible Moisturizer Broad Spectrum SPF 30 Sunscreen

$35.00, Fenty Beauty

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Isdin Eryfotona Actinica Daily Mineral Sun Protection with SPF 50+

$55.00, Amazon

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La Roche-Posay Anthelios 60 Clear Skin Dry Touch Sunscreen

$20.00,

BUY NOW

The Bottom Line

If applying sunscreen feels like an extra step in your routine that you're more likely to skip than not, it's time to reconsider your daily lineup. Without sunscreen, slathering on pricey wrinkle-fighters won't do any good — you're just reversing all your hard work by allowing harmful UV rays to wreak havoc on your skin.

So slather up, then join us for the next episode of The Science of Beauty. We'll be discussing how to treat one of the biggest skin issues that can result from not wearing sunscreen: hyperpigmentation.

Originally Appeared on Allure