Understanding SPF and How It Works in Your Sunscreen

One of the first things you look at while shopping for sunscreen is each product’s sun protection factor (SPF). The SPF of sunscreen offers an idea of how much protection you can expect against the sun’s harmful ultraviolet rays, which can irreparably damage your skin and cause painful acute sunburns. 

As experienced dermatologists, Vitaly Blatnoy, MD, and the team at Orlando Dermatology Center in Oviedo and Orlando, Florida, urge you to wear sunscreen every time you venture outdoors. Doing so protects your skin from sun damage and reduces your lifetime risk of skin cancer. 

So, why is sunscreen so important, and why does SPF matter? In this article, you’ll learn everything you need to know about SPF and how it works in your sunscreen. 

Why use sunscreen?

It’s hard to resist a summer beach day when the sun’s out. Whether you prefer to lounge in the sand or swim in the water, sun protection should be a priority before any outdoor time as the sun’s harmful rays can damage your skin rapidly and severely. Not only do they contribute to premature skin aging, but they can also irreparably damage the DNA of your skin cells and cause harmful changes leading to skin cancer. 

With more than 90% of skin cancers being caused by sun exposure, it’s best not to risk a day in the sun without sunscreen. Even low-SPF sunscreen is better than nothing. Regardless of the type of sunscreen you use, reapplying every two hours is important, especially if you’re sweating or swimming.

How sunscreen works

Sunscreen uses two different ingredient types to block or scatter sun rays so they don’t damage your skin as much or as quickly. Your favorite sunscreen might contain:

Physical (mineral) ingredients

Common minerals in sunscreens like titanium dioxide and zinc oxide reflect sun rays so they don’t penetrate and damage your skin. 

Chemical ingredients

Chemical compounds in sunscreen like octisalate and avobenzone absorb UV rays before they can penetrate and damage your skin. 

Both types of sunscreen ingredients are generally safe for your skin, but physical ingredients may be less likely to irritate sensitive skin. 

Choosing the right SPF for your skin 

The SPF labeled on a bottle of sunscreen gives you an idea of how long it would take the ultraviolet rays to burn your skin when used correctly versus using no sunscreen at all. For example, using sunscreen with SPF 50 would take your skin 50 times longer to burn than if you weren’t wearing any sunscreen. 

While a higher SPF offers longer sun protection when used correctly, don’t let it create a false sense of security. You should still reapply diligently and limit the time you spend in the sun to minimize sun damage on your skin. We recommend seeking shade, wearing a wide-brimmed hat, and covering up with breathable clothing garments in addition to wearing sunscreen, no matter which SPF you choose. 

If you have a family history of skin cancer or very fair skin, you should opt for a higher SPF. In general, everyone should use sunscreen with an SPF of at least 30 for outdoor activities. 

Our team can tell you everything you need to know about skin cancer prevention and sun protection. Schedule an appointment online or over the phone at your nearest Orlando Dermatology Center today.