All About Sunscreen Ingredients
We break down what’s in your favorite sunscreen, and why it works.
By now, you know you need it—and not only in the warmer months, but all year round. From beach trips to winter sports to everyday outdoor activities in between, sunscreen is a key part of any sun protection approach. But what exactly is sunscreen, and how does it really work? Here, we break it down, taking a look at what’s inside your favorite sunscreen products to help keep you sun-safe all year long.
What Is Sunscreen?
Sunscreen can take many different forms, and has just as many names to match: sunblock, sun cream, suntan lotion, or even just SPF (which stands for Sun Protection Factor). Whatever your preference, the basic function of sunscreen is the same across products—to form a topical, protective layer on the skin that both absorbs and reflects the sun’s harmful ultraviolet (UV) rays.
What are UV Rays and Why Are They a Problem?
The sun’s ultraviolet rays are generally broken down into two types:
- UVA: these rays are considered by most scientists and sun protection institutes to be the most common form, and they are what contribute to signs of premature aging.
- UVB: these rays are widely considered to be the most dangerous form, causing sunburns and other skin damage that can be harmful in both the short and long term.
In both cases, overexposure to ultraviolet rays can ultimately contribute to skin cancer. With this in mind, sunscreens that are labeled as Broad Spectrum are generally considered superior, as these SPF products can help to shield the skin from both forms of UV rays.
Speaking of SPF, you may be wondering why it takes the form of a number. While it doesn’t directly correlate to the time or duration of sun exposure (a common misconception), the SPF number is actually a measure of the amount of solar energy that would produce a sunburn on protected skin, as compared to unprotected skin. The higher the SPF, the greater the protection from harmful UV rays.
Common Forms of Sunscreen
While sunscreen is available in increasingly innovative forms, such as mineral powders and roll-on sticks, there are a few tried and true types that are the most popular and generally preferred ways to keep skin protected year round.
This popular sunscreen form has withstood the test of time, and for good reason. First, sunscreen lotions are easily portable, and can even be purchased in TSA-approved containers for worry-free air travel. Plus, with their creamy texture, lotions apply easily and consistently to the skin for full coverage that moisturizes throughout the day.
Building on the success of SPF lotions, sunscreen sprays can make it even easier to apply sun protection throughout the day—particularly on hard to reach areas like the back. Available in non-aerosol continuous sprays, as well as in pump sprays that simplify the application of creams, liquids, and even oil-based sunscreen products, sprays are a cinch to reapply. And that’s convenient, since most experts agree that we should reapply sunscreen at least every two hours—even more frequently when swimming or toweling off.
Water- and Sweat-Resistance
On that note, it’s important to keep in mind that no sunscreen is truly waterproof or sweatproof, since liquids break down the consistency and efficacy of sunscreens over a relatively short period of time. Instead, a sunscreen can be considered water- or sweat-resistant if its labeled SPF is still effective by either 40 or 80 minutes after its initial application, while you’re swimming or sweating. Regardless, it’s good practice to always reapply regularly and vigorously.
Primary Ingredients in Sunscreen
Sunscreen is powered by a variety of active ingredients that prevent the sun’s rays from harming your skin for a specified period of time that corresponds to the SPF number. Most sunscreen ingredients fall into two types:
- Physical Ingredients: also known as mineral ingredients, these are the elements that work to block the initial rays before they can go through the outer layers of the skin. You’re likely to see minerals such as titanium dioxide and zinc oxide listed for these.
- Chemical Ingredients: don’t be spooked by the name “chemical,” as these are important, non-toxic components of sunscreen that work to absorb UV rays as they hit your skin. You may see ingredients such as avobenzone and octisalate listed on labels.