Breaking Down Broad-Spectrum Protection: Why Your Sunscreen Needs to Have it

Anyone who has tried to choose a sunscreen knows you could spend hours comparing the brands, ingredients and formulations of the hundreds of products available. While plenty of your chosen sunscreen’s characteristics can be left up to personal preference, there are two things you shouldn’t compromise on: an SPF of at least 15, and broad-spectrum protection. (You’ll want a water-resistant, SPF 30 or higher sunscreen if you’re planning to spend significant time outside.) But while most people appreciate the importance of SPF value, they may not understand that broad-spectrum coverage is equally important.

One recent study showed this issue is very real — only 39 percent of consumers surveyed said that broad-spectrum protection was an influencing factor in their sunscreen-purchasing decisions. For comparison, 79 percent of consumers considered the sweat and water resistance of a product, and 75 percent considered the price of a product. The researchers guessed that many people don’t know what broad-spectrum protection is, so they don’t recognize how important a factor it should be in their purchasing decisions. So what exactly does this term mean, and why does it matter?

UVA and UVB: A Dangerous Combination

Most people on the hunt for a sunscreen already know that the sun’s ultraviolet (UV) rays are harmful. But not all UV rays are created equal, and understanding how each type affects the skin can reveal why keeping all of them at bay is crucial. There are three types of UV rays produced by the sun: UVA, UVB and UVC rays. UVC rays have the shortest wavelength of the three and are absorbed by the ozone layer before reaching Earth, meaning we don’t have to worry about protecting against them. UVB and UVA rays, however, do penetrate the Earth’s atmosphere and can reach our skin.

UVB rays are probably what comes to mind when you imagine harmful rays from the sun. These rays are the chief culprit behind skin reddening and sunburn, and vary in intensity depending on the weather, time of day and location. UVB rays cannot significantly penetrate glass, and they mostly damage the skin’s outermost layers.

While UVB rays can make their presence known with painful sunburns, UVA rays are a bit sneakier. UVA is the most prevalent form of UV radiation on Earth, accounting for up to 95 percent of the radiation that reaches the planet’s surface. They’re present with equal intensity during all daylight hours, and can penetrate clouds, fog and glass. UVA rays play a smaller role in sunburn than UVB rays do — but that doesn’t mean they aren’t dangerous. UVA rays are the chief tanning ray, and any sign of a tan means DNA damage. This type of radiation is also primarily responsible for premature skin aging, like wrinkles, because it penetrates more deeply into the skin than UVB radiation. UVA rays are also the primary ray in tanning machines.

Both UVA and UVB rays can damage the skin’s DNA to the point that genetic mutations occur — which can lead to skin cancer. Between the risk of sunburns, premature aging and skin cancer, UVA and UVB rays make an insidious team, and protecting against both is essential to keep your skin healthy.

A Broad Approach

Until recently, scientists didn’t fully understand the dangers of UVA radiation, so sunscreens weren’t expected to guard against it. As researchers gained more knowledge about the harm UVA rays can cause, sunscreen manufacturers began to incorporate ingredients that protected against them. Companies used the term “broad spectrum” to describe a sunscreen that protected against both UVA and UVB rays. It was a step in the right direction, but for a long time manufacturers didn’t have to meet any testing requirements to label their product this way, so the amount of UVA protection was often limited. In 2011, the FDA issued new rules for sunscreen labeling, which required any sunscreen on the market to meet FDA standards for both UVB and UVA protection before it could be labeled broad spectrum.

Here’s why that matters: A sunscreen’s SPF, which many people rely on to tell them how effective a product is, is first and foremost a measure of how long it takes UVB rays to redden the skin when using a sunscreen versus without the product. For example, if you apply SPF 15 sunscreen, theoretically it will take 15 times longer for your skin to start burning. This is already an imperfect model, since no sunscreen can be expected to remain effective longer than two hours. But in addition, if the product is not labeled broad spectrum, SPF doesn’t tell consumers anything about the UVA protection the product offers. Now, thanks to the FDA regulations, if the product is labeled broad spectrum, it means that the UVA protection is proportional to the UVB protection. The higher the SPF is, the higher the UVA protection will be as well.

Today, you can be confident in a sunscreen’s ability to protect you from UVA and UVB rays if you see “broad spectrum” and an SPF of 15 or higher on the label. It’s up to you to make that designation a priority, however! Do your skin the favor of keeping it safe from both types of harmful UV rays, not just one.