Sunscreen vs. Sunblock

We uncover the biggest differences and debunk popular myths surrounding sunblocks and sunscreens.

c-shells daily sunscreen

Who Needs Sun Protection?

Sunscreen is something we all know and (hopefully!) love, but let’s go back to the basics. Why do we need sun protection? Turns out, the sunlight that reaches us is made up of two types of ultraviolet radiation - long-wavelength UVA and shortwave UVB rays. These rays have a tremendous impact on our fragile skin: they cause sunburns, age skin prematurely, and increase the risk of skin cancer. Those sunspots on your face? Yep, that’s a sign of skin that’s unprotected from the sun. Evidence of visible sun damage on the skin can be as harmless as freckles to something life-threatening, like melanoma. UV exposure is cumulative over our lifetimes and responsible for 90% of the visible signs of skin aging. 

Needless to say, everyone needs sun protection. Even staying indoors exposes us to sunlight, as most clear windows don’t protect us from the sun. While it blocks most UVB rays (the ones that cause sunburn), glass lets in 62.8% of UVA rays, the ones that cause long-term skin damage like wrinkles (both rays can cause skin cancer). As long as the sun’s shining, we’ll need some form of protection. 

Sun protection comes in many shapes and sizes, but some are more practical than others. For example, staying indoors all day with our blinds closed is really not an option for most people. Hats can be stylish, but it neglects major parts of our skin. What’s one form of sun protection that is practical, adaptable, and ubiquitous? 

What's Sunscreen, Really?

Enter sunscreen. It’s a skincare product combining several active ingredients to help prevent UVA and UVB rays from reaching the deeper layers of skin. For the most part, it works by absorbing the sun’s rays and transforming them into heat, which is then released from our skin. The first major commercial sunscreen was sold in 1936. Since then, we’ve seen rapid improvements with how sunscreen is formulated and tested. In the United States, any product for skin that’s labeled with an SPF number can be considered sunscreen. SPF is a standard laboratory measurement of a sunscreen’s ability to prevent UVB damage to our skin. We recommend a skincare product that’s not only SPF 30 and above, but is also labeled “Broad Spectrum” (like our sunscreen, C-Shells!). This ensures that the product protects you against both UVA and UVB rays. We don’t believe in miracles, but sunscreen is pretty close to being that. 

Sunscreen vs. Sunblock

Now, onto the main question of “sunscreen” vs “sunblock”. There are two main types of sunscreens - chemical and mineral. A common belief is that “sunscreen” refers to chemical sunscreen, while “sunblock” is mineral sunscreen (to learn more about mineral vs. chemical sunscreen, see our post here). This misconception arises from a deeper misconception about how mineral sunscreens works vs. chemical sunscreens. At the end of the day, there’s really no solid scientific grounding behind such differences, and most people freely use the two terms interchangeably. Even brands and manufacturers themselves used these two terms synonymously to their whim. 

That all changed in 2011, when the FDA rolled out new regulations around sunscreen sold in the United States. As one of the many measures announced, SPF products were no longer allowed to be labeled as “sunblock” to avoid misleading consumers about whether the sun was effectively being “blocked”. (Remember, most sunscreens work by absorbing UV rays and turning them into heat.) Instead, with the hope of helping consumers make better-informed decisions about sun protection, “sunscreen” became the required term. 


Does that mean sunblocks no longer exist after 2011? Not quite. To this day, the term “sunblock” is casually used interchangeably with “sunscreen.” What it means though, is that you won’t see the product formally labeled as “sunblock” on shelves and in stores. No matter what it’s called, it’s important to make sure that you’re using some form of sun protection. We recommend sunscreen for everyone, because it’s effective, practical, and tested. There’re so many SPF products out there, but all you need is just that one that you’ll stick to every single day, for years to come. Trust us, your skin will thank you.