SEP 15, 2016 7:04 AM PDT

Sunscreen: Should You Buy Higher SPF?

WRITTEN BY: Xuan Pham
Does higher sun protection factor (SPF) really offer more protection against the sun’s rays? Though this seems like a logical conclusion, there a surprising lack of consensus for consumers. Now, results from a new study confirm that, indeed, higher SPF can reduce the risk of melanoma by 33 percent.

 
Ultraviolet (UV) radiation is the leading cause of skin cancer, also known as melanoma. There are 2 forms of UV rays: UVA and UVB. One simple way to keep track of these rays is by remembering that UVA is associated with aging, while UVB is associated with burning.
 
Those sunburns after a fun beach day? Those are caused by UVB, which is implicated as a key player in skin cancer. These types of rays are more intense during high noon, and relaxes a little when the sun goes down. By contrast, UVA rays are present at the same intensity throughout the day and season. Exposure to these rays accelerate skin aging, and can also promote skin cancer.
 
Sunscreen lotions offer protection against these harmful rays. However, when it comes to exactly how much that sunscreen is protecting your skin, the answer isn’t quite so simple. For example, the SPF number on the bottle of sunscreen is mainly an indication of UVB protection, meaning that UVA protection can be a sort of guesswork for consumers.
 

 The SPF number is also misleading in how it is derived in the lab versus how consumers use it in real life. Consider a sunscreen with an SPF 30. This means that the sunscreen would provide a factor of 30 sun protection before your skin would burn. In other words, if your skin burns after 10 minutes in the sun, then SPF 30 would theoretically let you stay 30 times longer (300 minutes) before burning.
 
But the reality is not quite so reassuring, as many beachgoers with sunburns can attest. This is because under practical, real-life conditions, people typically use a quarter to a half of what’s required to achieve the advertised SPF. Consequently, people are only getting, at best, about a third of the labeled SPF protection.
 
People are also terrible at reapplying the liberal amounts of sunscreen at regular intervals, too. This undermines the protection they can get.
 
Thus, if it seems that people are so bad at applying sunscreen right, giving them a higher SPF sunscreen to begin with could be an appropriate solution, right? As it turns out, this is not a fail-proof option either. High SPF can lull people in a false sense of sun safety – they may stay out in the sun for longer and dismiss seeking shade.
 
Not many people realize that SPF is not a linear scale – an SPF 30 does not equal twice the protection as an SPF 15. Rather, SPF 15 blocks 93 percent of UVB rays, and an SPF 30 offers an increase of 4 percent protection (97 percent of UVB rays blocked). Meanwhile, increasing the SPF to 50 buys you an increase in 1 percent of UVB protection (98 percent UVB rays blocked).
 
And so, how high can you go with SPF before the protection increase is negligible? According to Dr. Steven Wang, physician at the Memorial Sloan-Kettering Cancer Center and a member of The Skin Cancer Foundation, he recommends not going below SPF 30 and not above SPF 50.
 
Importantly, Wang also emphasizes that the sunscreen also have broad spectrum protection, which would cover UVA as well as UVB rays. “In addition to an SPF of 30+, your sunscreen should include some combination of the following UVA-blocking ingredients: zinc oxide, titanium dioxide, avobenzone, ecamsule, and oxybenzone.  Sunscreens with both UVA and UVB protection may be labeled multi spectrum, broad spectrum, or UVA/UVB protection,” said Wang.
 

Additional source: University of Oslo, Skin Cancer Foundation
About the Author
  • I am a human geneticist, passionate about telling stories to make science more engaging and approachable. Find more of my writing at the Hopkins BioMedical Odyssey blog and at TheGeneTwist.com.
You May Also Like
JUN 10, 2021
Cell & Molecular Biology
Does Lithium Prevent Colon Cancer?
JUN 10, 2021
Does Lithium Prevent Colon Cancer?
Researchers found that a drug used in the treatment of mental illness can promote the fitness of healthy gut stem cells, ...
JUN 26, 2021
Cancer
Immunotherapy Drug Shows Promise for Obese Patients with Breast Cancer
JUN 26, 2021
Immunotherapy Drug Shows Promise for Obese Patients with Breast Cancer
Research shows that obese patients with cancers including ovarian and melanoma may respond better to a certain kind of i ...
SEP 06, 2021
Drug Discovery & Development
Antibiotics Increase Colon Cancer Risk by 17%
SEP 06, 2021
Antibiotics Increase Colon Cancer Risk by 17%
People who take antibiotics are at an increased risk of developing colon cancer within five to ten years. The research w ...
SEP 16, 2021
Cancer
Inspiring Hope during Childhood Cancer Awareness Month
SEP 16, 2021
Inspiring Hope during Childhood Cancer Awareness Month
Childhood cancers, also known as pediatric cancers, are diagnosed in patients up to 14 years old.  Estimates for 20 ...
OCT 09, 2021
Cell & Molecular Biology
The Anti-Cancer, Copper-Binding Compounds Found in Fish
OCT 09, 2021
The Anti-Cancer, Copper-Binding Compounds Found in Fish
In the world's waterways, fish are confronted with endless challenges. For example, they have to defend themselves from ...
OCT 14, 2021
Cancer
Mechanism of Resistance to Colorectal Cancer Treatment Uncovered
OCT 14, 2021
Mechanism of Resistance to Colorectal Cancer Treatment Uncovered
Colorectal cancer develops when a series of changes occur across multiple genes.  While researchers have paid signi ...
Loading Comments...