Physical Sunscreen vs. Chemical Sunscreen: What’s the Difference?
Sunscreen is important. In fact, many skin care experts agree that it’s the most important part of your skin care routine because the sun is so detrimental to our skin. And the world of sunscreen is vast, and growing larger every day. There are hundreds of brands producing thousands of products, making it hard to know what to look for, let alone which one to buy. Some sunscreens leave you skin feeling oily and greasy, while others leave a white cast after they’re applied, making them particularly difficult to use for those with medium to dark skin tones. Certain sunscreens are water-resistant, while others aren’t recommended for contact with water. In what can seem like a fairly daunting market, we’re here to clear up some of the confusion.
Sunscreens fall into two categories: physical and chemical. Physical sunscreens, often called “sun blocks” are primarily comprised of mineral-based ingredients— things like zinc oxide & titanium dioxide, both of which block UV rays. Chemical sunscreens, on the other hand, are made up of chemical compounds. Instead of blocking UV rays, chemical sunscreens absorb them, converts them to heat, and releases them from the body.
Like we said, physical sunscreens are the more traditional “sun blocks.” By using minerals that naturally block UVA and UVB rays, physical sunscreens essentially act as a shield, deflecting the sun’s harsh rays. Because of this, physical sunscreens are often a better choice for those with sensitive skin. By deflecting UV rays, as opposed to absorbing them, physical sunscreen helps protect sensitive skin from heat-triggered irritations, like rosacea. Zinc oxide and titanium dioxide (the two major components of most physical sunscreen) have also been shown to be drastically less harsh for those with sensitive skin.
Physical sunscreen is also very fast-acting; since it works as a shield, your skin is ready for the sun the moment it’s applied. Spread a healthy amount on, rub it in, and you’re all set (most of us don’t apply nearly enough sunscreen—see chart below). Unfortunately, this makes physical sunscreens fairly easy to rub off. By nature, physical sunscreens are not waterproof, so if you’re going to be in the pool, you may want to consider a chemical sunscreen.
Unlike their physical counterpart, chemical sunscreens are comprised of compounds that are designed to absorb UV rays, convert them into heat, and release them from the body. These sunscreens tend to be lighter and thinner than physical sunscreens, making them easier to apply. Thinner sunscreens can be ideal for people with comprehensive skin care routines, as traditional physical sunscreens can often be heavier than moisturizers.
Those with sensitive skin are often not advised to use chemical sunscreen, as there is an increased risk of irritation. This type of sunscreen also takes about 20 minutes before it begins working, as opposed to the immediate results of the physical version. Fortunately, however, chemical sunscreens are waterproof and sweat proof, making them the far superior choice for sports or summer swims.
Don’t Skip Sunscreen
Regardless of which route you choose to go, don’t skip sunscreen. Study after study shows that the sun’s rays are the leading cause behind aging and damaged skin. Be sure to always use an SPF of at least 30 (anything less than that has been deemed inadequate for complete coverage). Apply sunscreen every day, as even your time spent driving or sitting by a window increases your likelihood of sun-based skin damage. Use this chart as a reference tool for how to make sure you’re giving your skin the preventative care it deserves.
British Journal of Dermatology, April 2007, pages 716-719
Photodermatology, Photoimmunology, & Photomedicine, Aug 2013, pages 221-224
Photodermatology, Photoimmunology, & Photomedicine, Dec 1993, pages 242-244
PLoS One, May 2018, pages 3-13