Physical vs. Chemical Sunscreens—Explained!

May 25, 2016
by Annalise Mantz for Thrive Market
Physical vs. Chemical Sunscreens—Explained!

I remember my first bad sunburn vividly. I spent most of every summer in my family’s backyard pool, and one day, it caught up to me—or more specifically, my nose, which turned hot pink and painful to the touch.

Naturally, my first concern was not being able to swim the next day (ah, the priorities of a 10-year-old). My grandma had a solution: a thick layer of chalky, white sunscreen, lifeguard-style, on my nose.

She knew something that I didn’t—sun protection is serious business. That’s why she reached for good ol’ zinc oxide to keep my skin safe.

To save yourself from a similar summer mishap, it’s helpful to know the difference between the two main types of sunscreen: physical and chemical. (They’re also sometimes referred to as “inorganic” and “organic,” respectively.) While both can protect you from the sun’s rays, they work in totally different ways. Here’s a breakdown on each—and how to pick the best one.

The basic reason we need sunscreen is to protect our skin from ultraviolet radiation, which the sun gives off 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. In fact, one study found that women who had five or more blistering sunburns between age 15 and 20 had an 80 percent greater risk of melanoma.

No matter which sunscreen you choose, you want one that blocks both UVA and UVB rays. Look for a sunscreen labeled "broad spectrum"—that means it offers protections from both types.

Physical sunscreen (aka inorganic)

As the name suggests, this type of sunscreen contains compounds that physically block ultraviolet radiation. Physical sunscreens used to be called “sunblock” for this reason—though the Food and Drug Administration banned manufacturers from using that sometimes misleading label in 2012.

Most products 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.

The only downside? Physical sunscreens can be thick, and often leaving an opaque white film even after you massage them in. That’s why my nose immediately turned white when my grandma slathered sunscreen on it—she was using zinc oxide.

Chemical sunscreen (aka organic)

This is the kind you’re most used to seeing on drugstore shelves. Instead of blocking the sun’s rays, chemical sunscreens use synthetic compounds to absorb and deactivate radiation, releasing it as heat. The skin absorbs these products easily, so they usually don’t leave behind any residue.

And though they do work to protect your skin, here’s the issue: Many of the chemicals inside have been linked to allergic reactions and even hormone disruption. The Environmental Working Group flags the following as some of the worst offenders:

  • 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. Most conventional, non-natural sunscreens are chemical.

So which is better?

Since both types offer equal sun protection, the choice really comes down to the chemical side effects. Physical sunscreen definitely wins that category—the EWG doesn’t list any side effects for either zinc oxide or titanium dioxide, and actually recommends zinc-based, broad spectrum sunscreen.

But that doesn’t mean you have to settle for chalky white skin either. Thankfully, beauty experts have developed a physical formula that goes on clear, doesn’t leave your hands sticky, and fully protects your skin: the Elemental Herbs SPF 30 Sunstick. Slather it on anytime you go out in the sun and reapply often—and make sure not to fall victim to any of the five most common sunscreen mistakes!

Editor's note: The original article did not include information about the FDA banning the label "sunblock." 

Photo credit: Alicia Cho

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This article is related to: Beauty, Health, Summer, Spring, Educational

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  • Science_Advocate

    One should really not use "chemical" to distinguish between the two types of sunscreen. Zinc oxide and titanium dioxide are technically both chemicals. In fact, dihydrogen monooxide, aka water, is also a chemical. Furthermore, may I point you to the link below from the research team at Paula's Choice? Upon closer examination of the scientific evidence mentioned there, you may find it necessary to amend this article. The EWG perhaps has not updated the article you cited and/or considered other more rigorous and replicated research. Finally, I believe that use of the term "sunblock" has been banned by the FDA for about three years now. It's misleading because the typical amount of sun cream applied by the average person will not completely block UV rays.

  • Lauren

    Zinc doesn't absorb rays. It reflects rays just like titanium does. Also, chemical and mineral sunscreens don't offer equal protection. Chemical sunscreen is less protective because the only ingredient that protects from the majority of UVA (or aging) rays, breaks down in the sun quickly. Zinc and titanium don't break down when exposed to the sun.

    Thanks for educating people on the importance of natural mineral sunscreen! It's important.