There’s a figure that has been circulating on the internet for years, stating that SPF 50 provides only about 1% more protection than SPF 30. While that figure is factual, people have been doing the SPF math all wrong. Although the percentage is small, it has a much bigger impact than we can imagine.
HuffPost spoke to three board-certified dermatologists, including two Mohs surgeons (specialists in skin cancer), to explain what that means and help determine the type of sunscreen we should use and why.
What does SPF 50 do?
SPF stands for “sun protection factor” and refers to the amount of protection against UVB rays. Before picking a sunscreen, “You need to know what percentage of the sun’s UVB rays are being filtered. For instance, SPF 15 is 93%, SPF 30 is 97%, SPF 50 is 98% and SPF 100 is 99%,” said Dr. Kenneth Mark, a board-certified dermatologist and Mohs surgeon.
“Numerically, there isn’t much of a difference between SPF 50 and SPF 30 but in real-world use, it is significantly better” said Dr. Margarita Lolis, a board-certified dermatologist and Mohs surgeon at Schweiger Dermatology Group in New Jersey. “Most people under-apply sunscreen, which lowers the actual protection against UVB rays. SPF 50 gives a better buffer in my opinion.”
The protection against UVA rays isn’t measured in the same way. “The SPF number has nothing to do with UVA protection,” Mark said.
In the U.S, the Food and Drug Administration mainly considers zinc and titanium dioxide-based sunscreens as offering adequate protection against both UVA and UVB rays. However, a broad-spectrum sunscreen is what you should be on the lookout for. Outside the U.S., you can look for a “PA rating,” which is common in Japan, or a “star rating” in Europe.
“While SPF 50 offers only 1% extra filtering of the sun’s UVB rays compared to SPF 30, if someone would burn in five minutes of sun exposure without any SPF, an SPF of 30 would allow them to not burn for 150 minutes, and an SPF 50 would allow them not to burn for 250 minutes,” explained Mark. In this example, we can see the difference between the two is significant.
“The SPF is measured by checking how long it would take skin to get red with sun exposure,” said Dr. Kiran Mian, a board-certified dermatologist at Hudson Dermatology and Laser Surgery in New York.
“The UVB value is calculated as the ratio of how much time it takes UVB radiation for skin to get red with sunscreen, divided by how much time it takes for skin to get red without that sunscreen,” Mian explained.
“The main idea is that the higher the number, the extra layer of protection of the typical margin of error of not applying properly or reapplying enough,” noted Mark.
Does SPF 100 offer double the protection of SPF 50?
No — that’s a myth, as sunscreen protection isn’t cumulative in that way. “SPF is not a linear scale; it is logarithmic,” Lolis said. “SPF ratings aren’t proportional to strength. SPF 100 isn’t double the SPF 50. In reality it offers 1% more protection.”
“SPF 50 allows for 1 out of every 50 UVB rays to enter, while SPF 100 allows 1 out of every 100 UVB rays to enter,” Mian explained.
The same goes for combining more than one sunscreen, thinking this will offer more combined protection. This is simply not true, explained Mian: “If you apply an SPF 50 on top of an SPF 30, it does not equal SPF 80. You are protected by the higher of the SPFs.”
When is SPF 30 good enough?
“If someone has medium to dark skin, does not usually burn, and has never had skin cancer, SPF 30 is sufficient,” noted Mian.
People with dark skin have a natural protection due to the increased melanin in their skin, but this isn’t an absolute protection from UVB rays, says Lolis. “Cumulative UV damage contributes to photo aging as well as skin cancers rarely, and dark-skin individuals are more prone to post-inflammatory hyperpigmentation” she added.
Even if you opt for an SPF 30, you should still be careful in higher-risk parts of the body, such as the palms of hands, soles of feet, and lighter parts of the body, noted Mark.
On the other hand, an SPF 50 is highly recommended in the following cases: for children, people who burn easily, anyone who has prolonged sun exposure (beach or a hike), people with a history of skin cancer, melasma, post-inflammatory hyperpigmentation, acne or rosacea, and people with sensitive skin.
Additionally, an SPF 50 is preferred to SPF 30 for anyone on photosensitive medications, those who are immunosuppressed, and those who have recently had procedures (like lasers, peels or microneedling).
Sunscreen misconceptions
“Theoretically, a higher SPF does offer longer protection. However, things like sweating, rubbing the skin, or swimming make SPF not last as long, so reapplication is key,” Mian said.
All experts agreed that most of the time people aren’t applying enough sunscreen to reach the advertised level of SPF. For example, three people could all apply an SPF 50, and one could get SPF 50-level protection, one SPF 30 protection and one SPF 20 protection, noted Mark.
Paying attention to the amount of sunscreen applied is of the utmost importance. “You need 2 milligrams per square centimeter of skin to get the listed level of sun protection, which is about 1/4 teaspoon for the face and one shot glass for a full adult body. Since most people are not measuring their sunscreen before applying it, I tell my patients to apply two full finger lengths of sunscreen for their face and neck,” Mian said.
“The classic example was from about 30 years ago, where we learned the typical person applying an SPF 15 — the most popular maximum at the time — was actually getting an SPF of 4! Therefore, if you do not apply enough, you do not get the stated level of protection,” Mark said.
Another issue is thinking a higher SPF will last all day, potentially leading to people skipping reapplication, noted Lolis.
“Using a higher SPF isn’t the only reason people don’t reapply,” Mark said. “Regardless, it is very challenging to perfectly apply initially and to reapply properly throughout the day, so the higher SPF does help protect somewhat against that margin of error,” he added.
Verdict: Is SPF 50 Actually That Much Better Than SPF 30?
Although SPF 50 (and SPF 100) is better than SPF 30 in terms of the overall protection of the skin, it may create a false sense of security, leading people to forgo reapplication and think they are fully protected for longer.
“Application quantity is so extremely important and one of the biggest pitfalls that patients fall into. When you do not apply enough sunscreen, you are drastically reducing its effectiveness,” noted Lolis.
A higher SPF value is very significant if you are prone to skin cancer, have very light skin prone to sunburn, or are in strong sun for a prolonged period, Mian said.
No matter the SPF you pick, ensure you apply the appropriate amount and reapply every two hours, or sooner if you’ve been swimming, sweating or exercising. Adding another layer of protection, like an umbrella, hat and UV clothing is also helpful.
Looking for a good SPF? These come highly recommended.
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EltaMD UV Restore SPF 40
If you're looking for a sunscreen that doubles as anti-aging skin care, board-certified dermatologist Dr. Sonia Badreshia-Bansal recommended the EltaMD UV Restore sunscreen. She said, "sunscreens that combine physical blockers with antioxidants like niacinamide, vitamin C, or DNA-repair enzymes" can help combat oxidative stress and visible signs of aging. This particular SPF has with squalane and ginger root extract, both of which support skin health and appearance.
Ultra Violette Future Screen SPF 50
The cult-fave Australian brand Ultra Violette is finally available in the US at Sephora! If anyone knows how to protect their skin from harmful rays, it's Southern Hemisphere-dwelling Australians. I stock up on their sunscreens and lip balms every time I'm Down Under, and this development is a real thrill for skin care lovers. Board-certified dermatologist Dr. Jessie Cheung of Chicago’s Cheung Aesthetics & Wellness told HuffPost that this must-have SPF is “packed with mineral blockers to protect from the harsh Aussie sun, but feels silky and lightweight.”
Isdin Eryfotona Actinica SPF 50+
Both Badreshia-Bansal and Cheung recommended this Barcelona-based skin care brand's sunscreen. It is 100% mineral-based and infused with skin-loving ingredients that make it a great multitasker. It is one of the most comfortable mineral sunscreen formulas I’ve tried. It’s formulated with zinc oxide, DNA repair enzymes and vitamin E — so not only is it preventing sun damage, but it’s helping to nourish and repair the skin as well.
The Isdin sunscreen is significantly lighter and easier to blend than traditional mineral SPFs, and doesn’t have that lingering zinc smell that personally drives me up the wall. It dries down to a soft matte and is a nice base for dewy makeup looks. While this sunscreen blends well, there is a very slight white cast that’s typical of a mineral sunscreen formulation. The combination of lightweight finish, formula and UV protection has made it worth the troubleshooting. Many shoppers noted that it’s great for anyone who has sensitive skin, rosacea and skin cancer.
Neutrogena Sheer Zinc Oxide Dry-Touch mineral sunscreen SPF 50
When you're going to hit the beach or pool, water-resistant formulas are key. Badreshia-Bansal said, "Look for something labeled ‘water resistant (80 minutes)’ and at least SPF 50. I recommend mineral sticks or lotions because they tend to be more photostable." In previous reporting, Dr. Brandan Camp, a board-certified dermatologist at MDCS Dermatology, said, "This lightweight, non-greasy product provides SPF 50 protection and contains zinc oxide as the active ingredient," Camp said. It's specially formulated with antioxidants to be water-resistant, is naturally sourced and dries down quickly without leaving a greasy finish.
Elemis Pro-Collagen SPF 50
This silky sunscreen is one of Elemis' newest products, but given how great it is, you'd think the brand has been in the SPF game for decades. I've been using it for a couple of weeks and absolutely love it. I'm extremely fussy about sunscreen texture, finish and scent — and luckily this beauty knocks it out of the ballpark on all counts while providing powerful SPF 50 protection. It's a sheer, imperceptible fluid that dries down quickly with no white cast and leaves your complexion looking radiant and dewy, never greasy. I can't help but add it to this list of must-haves that your skin will love.
EltaMD UV AOX mist SPF 40
For beach days, Cheung recommends a water-resistant SPF, preferably a mineral formula that won’t cause your eyes to sting or slide off when you're sweating in the sun. She pointed out that the EltaMD UV AOX Mist is great for full body coverage, since it "sprays on white but dries clear, so you won't miss any spots. It also has 360-degree sprayability, so you can apply it upside down."
La Roche-Posay Anthelios tinted light fluid sunscreen SPF 50
Badreshia-Bansal said, "I’m really impressed by the new La Roche-Posay Anthelios mineral tinted SPF 50+ Fluid – it’s sheer, has a universal tint, and offers high UVA/UVB protection with 100% mineral filters. It’s ideal for sensitive skin and has a great, elegant feel." Perfect for those days when you don't want to wear makeup want an easy pick-me-up.
CeraVe AM Facial Moisturizing Lotion with SPF 30
According to Witkowski, this CeraVe lotion with SPF 30 is "an excellent, affordable and widely accessible option for a daily morning routine." It provides sun protection while doubling as a moisturizer and is formulated with ceramides, hyaluronic acid and niacinamide to support skin barrier health and hydration while also soothing irritation.. He also pointed out that it's non-comedogenic and fragrance-free, making it appropriate for sensitive and acne-prone skin.
Blue Lizard Sensitive mineral sunscreen SPF 50+
Another Badreshia-Bansal recommendation for days spent outdoors, this reef-safe mineral sunscreen from Australia contains no active chemicals and is suitable for use on sensitive skin. It's also sweat- and water-resistant for up to 80 minutes so you can enjoy all types of outdoor activities without worry.
Merit The Uniform tinted mineral SPF 45
This sunscreen from the internet- and celeb-beloved beauty brand Merit is hot off the presses, and promises to be a lovely choice for those who want a sunscreen option that also offers a soft splash of color. It features a formulation that's designed to be lightweight and buildable with a silky, soft and velvety sheer finish to impart a natural glow, while also helping to smooth and blur the look of skin. It's available in 15 blendable hues. Be one of the first to check out this SPF.
La Roche-Posay Anthelios Clear Skin Sunscreen Dry Touch SPF 60
Having earned The Skin Cancer Foundation's Seal of Recommendation, this La Roche-Posay is Witkowski's personal favorite and “go-to” sunscreen, both for daily use and for days with extended sun exposure. It's also what he uses on his four-year-old child on beach days, bike rides or hikes. He noted that this oil-free SPF is very popular among dermatologists and is formulated with antioxidants that can help protect the skin from environmental damage. He also noted that it contains senna alata, "a tropical leaf extract known for its ability to combat oxidative stress and support the prevention of premature skin aging." You can't go wrong with this non-comedogenic, water-resistant formula that is also well-suited for sensitive skin.
EltaMD UV Clear SPF 46
Badreshia-Bansal echoed the saying that "the best SPF for daily use is one that you'll actually wear — lightweight, invisible and comfortable under makeup." She recommends a mineral SPF with low irritation potential, like this cult-fave SPF that is beloved by both HuffPost readers and editors alike. It's formulated with hyaluronic acid to deeply moisturize skin while the inclusion of lactic acid lightly exfoliates skin and can help to reduce hyperpigmentation and shine. It's a great option for people like me with sensitive and acne-prone skin. I turn to it anytime I'm going to be spending a lot of time in the sun or when I'm post-procedure and want to protect my skin without irritating it.
TiZO2 facial sunscreen and primer
"I recommend Tizo 2 Facial Mineral Sunscreen SPF 40 for individuals seeking both high-performance sun protection and anti-aging benefits," said Witkowski. It's enriched with powerful antioxidants that canhelp neutralize free radicals and support overall skin health, while the gentle formulation makes it well-suited for sensitive and post-procedure skin. He also pointed out that it has a matte finish that "wears comfortably under makeup."
Lancer mineral Sun Shield universal tint SPF 30
Cheung recommends a lightweight, tinted mineral SPF with antioxidants for everyday wear, like the Lancer Mineral Sun Shield SPF. "It multitasks as sun protection, skincare and a glow-up in one," she said. The iron oxides that provide the tint can also help to protect your skin from blue light, which penetrates deeper than UVB and contributes to hyperpigmentation. She added that this sunscreen "soothes while protecting and reducing sun damage, and will blend into all skin tones."