Physical vs. Chemical Sunscreens, Explained

Nothing spoils a beautiful day at the beach like a sunburn. Aside from the obvious discomfort, getting toasted by the sun’s rays increases your risk of developing melanoma, a particularly dangerous kind of skin cancer.

The sun gives off ultraviolet radiation at two different wavelengths: UVA and UVB. Longer-wave UVA rays penetrate the skin more deeply than UVB, but both can cause sunburns and skin cancer. To save your skin, add sunscreen to your daily routine—but with so many options, how do you choose the right one? It starts with knowing the difference between the two main types of sunscreen: physical (also called mineral) sunscreen and chemical sunscreen. While both can protect you from the sun’s rays, they work in different ways. Here’s a breakdown on each—and how to pick the best one.

Heads up: no matter which specific sunscreen you choose, you want one that blocks both UVA and UVB rays. Look for a sunscreen labeled “broad spectrum,” which means it offers protections from both types.

Physical Sunscreen

Also known as mineral or inorganic sunscreen, this variety contains compounds that physically block and reflect ultraviolet radiation. Most physical sunscreens include one of two key ingredients: titanium dioxide or zinc oxide. Because it’s derived from titanium—a highly reflective white mineral—titanium dioxide reflects and scatters light. Zinc oxide, on the other hand, absorbs rays. When a product lists either of these ingredients, you can be sure it’s a physical sunscreen. In 2019, the Food and Drug Administration proposed new regulations stating that titanium dioxide and zinc oxide are the only sunscreen ingredients considered “GRASE” or “generally recognized as safe and effective.”

If you’ve typically avoided physical sunscreens because of their reputation for being thick or heavy (or for leaving a white cast on the skin), take another look. Innovations in clean skincare has led to more physical sunscreen options, including clear and tinted versions that may work better for darker complexions. Conveniently, physical sunscreen starts working as soon as you apply it.

Chemical Sunscreen

Instead of blocking the sun’s rays, chemical or organic sunscreens use synthetic compounds to absorb and deactivate ultraviolet radiation, releasing it as heat. Chemical sunscreens are typically thinner and more easily absorbed than physical sunscreens, so they usually don’t leave behind any residue.

Since chemical sunscreens are absorbed into the skin, reading and understanding the ingredient list is crucial. Some ingredients commonly found in chemical sunscreens have been linked to allergic reactions and hormone disruption. The Environmental Working Group has identified the following chemical sunscreen ingredients as being potentially toxic:

• Avobenzone
• Homosalate
• Octinoxate
• Octisalate
• Octocrylene
• Oxybenzone

Any sunscreen that contains the ingredients above—or any chemicals other than titanium dioxide and zinc oxide—is considered a chemical sunscreen.

Which Kind of Sunscreen is Better?

In 2020, the FDA reported the results of a long-term clinical study on sunscreen ingredient safety. Research found that a number of common chemical sunscreen ingredients are absorbed into the bloodstream quickly and can remain there for extended periods of time, leading the organization to seek additional information about the safety of these ingredients.

If you’re trying to limit your exposure to potentially toxic chemicals, a physical or mineral sunscreen may be the safer choice—and not just for you. While chemical sunscreens may damage coral reefs and other marine life, physical sunscreens are safe for our oceans, meaning a better beach day for all.

Editor’s note: this post was updated in 2021.