After last summer’s big debate over sunscreen ingredients and our coral reefs (read  about the Hawaiian ban here), most of us having been paying more attention to what we’re slathering on in the sun.  

Picking the perfect product is about more than just the right SPF number for your skin type. Here’s everything you need to know read the label on your sunscreen without total confusion. This guide comes to us from our friends at Free People …

Physical vs. Chemical

First things first: understanding that there are two types of sun protection. Physical sunscreen (also known as mineral sunscreen) creates an actual barrier between your skin and the sun by basically sitting on top of your skin; the sunscreen is a fortress wall, with your skin on one side and your enemies (UV rays) on the other. Chemical sunscreen sinks into your skin and absorbs UV rays, then converts them to energy that’s less damaging to the skin.

Active vs. Inactive

Now onto ingredients in sunscreen. Again, there are two types found in sunscreen and they’re all listed on the label. As the name suggests, active ingredients are the ones that actually do the UV filtering and protect our skin from UV rays while the inactive ingredients are the extras, like the lotion that carries the active ingredients so you can slather ‘em all over. Both active and inactive ingredients can be physical, chemical or a combination of both — it just depends on the formula.

UVA vs. UVB

The sun is a multi-faceted star and thus can affect us in multiple ways, most notably with UVA and UVB rays. The first, UVA, get deeper into skin. They’re the ones that can cause wrinkles, aging, all that fun stuff. UVB targets the top layer of your skin and is responsible for all your super-fun sunburns. Since both types of rays are present at all times, you need sun protection that can handle both. As physical sunscreens form a literal barrier, they’ll protect you from every angle. If you opt for a chemical sunscreen, you’ll need to make sure it can handle UVA and UVB rays.

Common Ingredients In Sunscreen

Now, onto the good stuff. This is a list of the most common ingredients you’ll find in sunscreen, both physical and chemical. Make sure to read ingredient lists carefully before you decide on a product: doing so could be the difference between a raging sunburn and a pleasant day at the beach.

Avobenzone: One of the only chemical blockers that can protect against both UVA and UVB rays. It can be a bit unstable, though, especially when exposed to sunlight (ironic, right?), so be sure a physical blocker is also on the ingredient list for guaranteed protection.

Octinoxate: One of the most popular chemical UVB blockers, you’ll find octinoxate in a wide array of conventional sunscreens. That said, prolonged exposure to sunlight can change the chemical structure of the ingredient, making it less effective.

Octisalate: Another chemical UVB blocker, octisalate is also slightly degraded by exposure to sunlight and therefore needs to be paired with another UVB-blocking ingredient to effectively protect skin.

Octocrylene: The most stable chemical UVB blocker on the market. That said, it can cause topical reactions and irritations if you’ve got particularly sensitive skin, so proceed with caution.

Oxybenzone: Yet another broad-spectrum, chemical blocker (though it only protects against short UVA rays so make sure there’s a slew of other ingredients on the label). A common enough ingredient, but proceed with caution: oxybenzone has been cited as highly problematic for the world’s coral reefs and the EWG lists it as an endocrine disruptor and potentially toxic to the human body — learn about it here.

Titanium dioxide: A physical, mineral ingredient that protects against both types of UV rays, making it a broad spectrum blocker, you’re all but guaranteed to find titanium dioxide as one of the first things listed on a mineral sunscreen ingredient list.

Zinc oxide: The fan favorite among sunscreen purists, zinc oxide is a highly stable, broad spectrum (short and long wave UVA rays, and UVB) physical option. If you’re not into the look of a white mineral smeared all over your skin, opt for a product that contains nanoparticles of zinc oxide — they’ll blend into skin better.

Discover our favorite non-toxic sunscreens of all time here.