WTF do all those ingredients on my sunscreen bottle actually mean?

Ask any derm: Of all the beauty products in your arsenal, sunscreen is by-and-large the most important, but it also happens to be the most confusing. As words like “mineral blockers,” “broad spectrum UV,” and “reef safe” become more common in the conversation surrounding sun protection it’s critical to understand what the heck all of those ingredients on the label actually mean.

“In the United States, sunscreen manufacturers are required to list the ingredients active and inactive ingredients on the label. The active ingredients in sunscreens are the UV filters that protect our skin from UV rays. The inactive ingredients are the carrier lotion that holds the UV filters,” says dermatologist Dr. Terry Zickman, founder of Love Sun Body. “The active ingredients can be chemical, mineral, or a combination of both. Similarly, the inactive ingredients can be chemical, natural or a combination of both.”

First up: Understanding the different types of sun protection products out there on the shelves. There are two different types of sunscreen ingredients on the market—”physical” and “chemical”—both of which protect your skin from the sun’s rays, but in different ways. Physical sunscreens create a literal physical barrier between your sun and the skin to form a protective barrier, while chemical sunscreens skin into your skin to absorb the UV rays.

Speaking of UV rays, there are two primary types that you need to worry about: UVA, which penetrate the deep layers of your skin to cause aging and wrinkles; UVB rays hit the top layer of the skin and lead to sunburns and, over time exposure to both could lead to skin cancer. So in order to ensure you’re completely protected, you want to use a product that will work against both—otherwise known as “broad spectrum.”

While mineral filters are able to work double duty to keep you safe from both types of rays (lookin’ at you, zinc oxide and titanium dioxide!), if you’re opting for a chemical sunscreen you’re going to want to look for something with some combination of the two. Since they’re not all ingredients (and thus, sunscreens!) are created equally, we broke down the most important ones—and what you should know before slathering them all over yourself this season.

UVB Protection

Octocrylene: Octocrylene is the most highly stable of the UVB blockers, and is a great option if you want to go the chemical route. But sensitive-skinned peeps beware: It can cause irritation or allergic reaction in certain skin types, so best to do a patch test before rubbing it all over your face and body at the beach.

Octisalate: Consider octisalate your “middle of the road” UVB ingredient. It degrades slightly when exposed to sunlight, so it’s not quite as potent as octocrylene, and needs to be combined with another UVB-blocking element in order to actually provide enough protection to your skin.

Octinoxate- When it comes to blocking out UVB, octinoxate has got you covered—it’s the most popular UVB blocker in the industry. But, it’s worth noting, it’s far from a perfect ingredient. “When octinoxate is exposed to sunlight, it is changed to a less UV-absorbent form, which would seem to compromise its effectiveness,” says Dr. Zickman, pointing to a few pieces of evidence to back this claim. For instance, multiple studies have shown that octinoxate degrades in the sun and that it’s abilities to work go down with it. That and, it was recently one of Hawaii’s two banned ingredients because it can impact the coral reefs, so only wear it if you have no plans to hit the beach.

UVA Protection

Avobenzone: Of the two chemical UVA blockers, avobenzone is overall the better option. As far as safety risks goes, the EWG rates it toward the lower end of the spectrum (at a two, to be exact), but one thing to keep in mind when opting for a chemical ingredient over a mineral one? Avobenzone isn’t a highly stable ingredient on its own, so it needs to be paired with another ingredient to stabilize it. “Chemical sunscreens are absorbed into the skin and absorb UV radiation—upon being exposed to UV rays, they break down and release heat into skin,” explains Dr. Zickman. “Because chemical filters are absorbed into the skin, the UVA rays (responsible for more serious damage) reach deeper layers of skin.” On the other hand, mineral filters create a physical barrier on the top of the skin, and don’t break down and release any heat into the skin.

Broad Spectrum

Oxybenzone- Oxybenzone, a chemical compound, is technically a broad-spectrum ingredient, but it only protects against short UVA rays—not long ones, so you’ll usually see it paired with other ingredients on a label. Aside from that, though, oxybenzone has an entirely different set of things to think about when using it. For starters, as far as “reef safe” ingredients go, oxybenzone is a major offender, and it was one of the other banned sunscreen ingredients in Hawaii.

That’s not all: In 2018, the EWG rated it as a level 8 out of 10 for health concerns) because it acts as a hormone disruptor, and last month the FDA released a report that there was not enough data for them to determine whether the ingredient was generally recognized as safe and effective. So while broad spectrum protection is undoubtedly important, it’s probably worth getting it from other sources, instead.

Titanium dioxide: There are two mineral ingredients that the FDA has approved as broad spectrum blockers. Titanium Dioxide protects against UVB and short UVA rays, making it a staple in most mineral ‘screens.

Zinc oxide: This brings us to dermatologists’ (and lifeguards’) favorite sunscreen ingredient: zinc oxide. It’s highly stable, and protects against UVB rays and both short and long wavelengths of UVA. Dr. Zickman suggests looking for formulations that are at least 20 percent zinc oxide, because at low concentrations, the UVA protection becomes insufficient. Be sure to look for “non-nano” zinc and titanium dioxide, because those are the only formulations that are considered reef safe and that will sit on top of skin to keep the rays at bay.

Here’s why you should be wearing sunscreen 365 days a year, plus our favorite mineral sunscreens to help you do it.