Is SPF 15 Enough? Understanding Sun Protection Factor.
For decades, Americans have been warned of the risk of skin cancer from exposure to the sun's UV rays and encouraged to make sunscreen use a daily habit. Despite advisories from physicians, however, most Americans do not regularly use sunscreen. In fact, a survey published by the Centers for Disease Control (CDC) demonstrates that only 14.3% of men and 29.9% of women report regular use of sunscreen on their face and other exposed areas of skin.
Among those consumers who do use sunscreen regularly, there is a lot of confusion. According to a 2015 study, most individuals select a sunscreen based on the SPF number alone, with preference given to higher numbers. Other important factors, like whether or not the product offers broad-spectrum protection and its ability to protect skin from photoaging are factors that rarely come into play in the buying decision.
Here at Lexli we can attest to how important that SPF number is to customers. Because our products typically incorporate SPF 15 (with the exception of Day Moisturizer with AloeGlyC® Complex, which uses SPF 30), we are often asked, "is SPF 15 enough?" Before answering that, let's first walk through an overview of SPF.
SPF - What Does It Mean?
SPF stands for sun protection factor and the SPF number represents how long you can stay in the sun without burning. For example, if it typically takes 30 minutes in the sun before your skin begins to burn, SPF 15 will extend that time by 15 (30 minutes x 15 = 450 minutes). SPF 30 extends the time before burn to 30 (30 x 30 = 900), etc. These estimates are based on proper sunscreen application, which we'll get to in a bit.
Additionally, SPF numbers tell us the percentage of UVB rays - the rays that cause our skin to burn - the product can absorb. In vitro tests show that SPF 15 absorbs approximately 93% of UVB rays, while SPF 30 absorbs approximately 97%. Beyond this, the absorption rate goes up minimally. SPF 50, for example, absorbs approximately 98% of UVB rays, a minimal increase from SPF 30.
While SPF measures protection from UVB rays, UVA rays are also harmful. UVA rays are the type of ultraviolet radiation responsible for photoaging while contributing to certain types of skin cancer. UVA rays damage the skin without burn so you do not instantly see their negative impact on the skin. However, exposure to UVA rays is cumulative so each exposure does leave a mark.
The only way to ensure the sunscreen product you use provides protection from both UVA and UVB rays is to look for the words "broad-spectrum coverage" on the label.
Proper Usage Is Vital
Despite the protection that a sunscreen is formulated to deliver, many individuals do not experience that level of coverage. This is because many of us not apply enough sunscreen, at the right time, or as frequently as necessary. On average, it takes 1 ounce of sunscreen - an amount equivalent to a shot glass - to get the protection advertised by the product. And because sunscreen takes time to absorb, apply it 15 to 30 minutes before going outdoors. Sunscreen effectiveness is reduced by sweating and water exposure. To ensure coverage maintains stable, sunscreen should be applied every two hours.
Is SPF 15 Enough?
So back to that original question: Is SPF 15 enough?
Many dermatologists and even the Skin Cancer Foundation suggest that SPF 15 provides a good basic level of coverage for everyday activities. Sunscreen often feels increasingly heavy, sticky and even greasy as the SPF level increases and because consistent daily use is the goal, SPF 15 is a comfortable level for most people. With protection from 93% of UVB rays, consumers can feel confident that they're getting a solid degree of protection.
For intense sun exposure - such as a day at the beach or for those individuals who work outdoors - there is benefit in using a sweat- and water-proof product with SPF 30, which protects from 97% of UVB rays. While you can certainly choose a higher SPF product for increased protection, the minimal increase in protection often comes with a higher price. For that reason, we don't advise selecting a product with an SPF higher than 50.
In summary, our sunscreen guidance is this: Use a broad-spectrum sunscreen product with a minimum of SPF 15 every single day and ensure that you are using the proper amount. (Tip: use a daily moisturizer with added SPF like Day Moisturizer with SPF 15 to make it easier to remember your sunscreen.) Select a product that feels good on your skin so you're more likely to be consistent. While reapplying a sunscreen lotion every two hours can be difficult if you're wearing makeup, consider using a spray sunscreen that can be applied over the top. Finally, when outdoors for extended periods of time, use protective clothing like wide-brimmed hats or rashguards to protect your skin. After all, sunscreen isn't intended to be your only means of protection.