Dermatologist Answers: What Does SPF 50 Mean?
Sophia Ahmed
We hear it all the time, especially when we are shopping for skincare products: SPF. But what exactly does it mean? SPF stands for Sun Protection Factor, which measures how well a sunscreen protects your skin from the harmful ultraviolet (UV) B rays from the sun. The number following SPF indicates the level of protection against UVB rays, with higher numbers offering more protection. For example, SPF 30 blocks around 97% of UVB rays while SPF 50 blocks around 98%. It is important to note that SPF only indicates protection against UVB rays and not UVA rays, which also contribute to skin damage and aging. Therefore, it is recommended to use a broad-spectrum sunscreen that protects against both types of rays.
Before the FDA introduced its new labeling requirements a few years ago, SPF levels caused a lot of confusion for customers. Some people thought that the SPF number corresponded to the number of minutes the sunscreen protected the skin, the percentage of rays the sunscreen filtered, or other misguided logic. The SPF number theoretically correlates to how long a person can stay in the sun without burning. For example, when wearing an SPF 30, you can remain outside for 30 times longer than if you were unprotected. However, that doesn’t take into consideration your skin type, any toweling, swimming, sweating, or the level of the UV index that particular day. Confusing, right? Now, all sunscreens have mandated directions and water resistance testing results visible on their packaging. Sunscreen can either be effective for up to 40 minutes or up to 80 minutes in water. It’s much easier for people to understand the need to reapply at least every 2 hours. You should reapply every 40 or 80 minutes while swimming or sweating, depending on the product. These directions are now easily seen on the packaging. An SPF 50 offers a high level of protection and is best for those with a history of skin cancer or those that are fair-skinned or at higher risk for skin cancer. An SPF 15 covers 93% of UVB rays and an SPF 30 covers 97% of UVB rays. There is a fairly big difference between an SPF 15 and 30 but the difference in coverage lessens considerably between SPF 30 and SPF 50. The protection afforded by-products over SPF 50 is only incremental.
Protecting our skin from the sun's harmful rays is essential, and choosing the right sunscreen with the appropriate sun protection factor (SPF) is crucial. The SPF measures the sunscreen's ability to shield the skin from UVB rays that can cause reddening and skin damage. The different levels of SPF provide different degrees of sunburn protection, ranging from 15 to 100. SPF 15, for instance, filters out 93% of UVB rays, while SPF 50 blocks out 98%. It's important to know that SPF does not measure the level of UVA protection, which can cause aging and skin cancer. Hence, it is advisable to choose a sunscreen labeled "broad-spectrum" to ensure overall skin protection. Experts recommend using SPF 30 or higher and applying generously every two hours to avoid sun damage. Take care of your skin and enjoy the sun safely!
We all know that protecting our skin from the sun's harmful rays is important, but do we actually understand how UVA and UVB rays impact skin protection? UVA rays, while present all year round, are the primary cause of premature aging and can pass through clouds and glass. On the other hand, UVB rays, which can cause sunburn, are stronger during the summer and are blocked by glass. Both types of rays can damage the DNA in our skin cells, leading to skin cancer. Understanding the differences between UVA and UVB rays can help us make informed decisions about how to protect our skin from the sun. So next time you reach for sunscreen, think about the type of protection you need to stay safe in the sun.
After all, the doctors always have a better say in recommendations, here are a few listed: