How to Choose Between Physical vs. Chemical Sunscreen, According to a Derm

Spoiler alert: SPF is very important (yes, even if you’re spending the day indoors). Whether you prefer a gel, stick or cream-based sunscreen, it’s really not the form that matters as much as the type. If you’ve heard the terms “chemical” and “physical” tossed around, but aren’t sure what exactly they mean, you’ve come to the right place. We reached out to a derm to give us the lowdown on each type of sunscreen, including how to choose the best one for you.

Physical sunscreen (also known as mineral sunscreen) sits on the top of the skin to block the UV rays from penetrating through the skin. It contains active mineral ingredients such as zinc oxide and titanium dioxide.

“Physical sunscreens are inherently broad-spectrum, shielding the skin from both UVA and UVB rays. Zinc oxide offers the most thorough protection; titanium dioxide is second best,” said Dr. Hadley King, a NYC-based dermatologist.

Get the sunscreen: Cerave Mineral Sunscreen Lotion SPF 50 ($12); Guards Up Daily Mineral Broad Spectrum SPF 35 ($22); Brush on Block ($32); EltaMD UV Clear Broad-Spectrum ($36); Coola Organic Mineral Sun Silk Creme SPF 30 ($42); Eleven by Venus Williams Unreivaled Sun Serum SPF 35 ($50)

Some read the word chemical and run for the hills, but it’s not as bad as you think. While physical sunscreen works to block the UV rays, chemical sunscreen protects your skin against UVB rays by absorbing into the skin. The ingredients found in chemical sunscreens are usually a combination of these organic compounds: oxybenzone, octinoxate, avobenzone, octisalate, octocrylene and homosalate.

“Chemical sunscreens are made up of chemicals that absorb the UV rays and create a chemical reaction that changes the UV rays into heat and the heat is then released from the skin,” said Dr. King.

Get the sunscreen: Neutrogena Ultra Sheer Dry-Touch Sunscreen SPF 70 ($9); INNISFREE Daily UV Defense Sunscreen SPF 36 ($15); Black Girl Sunscreen ($19); La Roche-Posay Anthelios Clear Skin Dry Touch Sunscreen Broad Spectrum SPF 60 ($20); SHISEIDO Ultimate Sun Protector Lotion SPF 50+ Sunscreen ($25); Supergoop! Glowscreen Sunscreen SPF 40 ($36)

The biggest difference between chemical vs. physical is how it lays on your skin—chemical absorbs, while physical sits on top. However, there are other key differences between the two. Here are a few things to consider when making your purchase:

• How often it’s applied: Chemical sunscreen requires 20 minutes to absorb after applying before you can confidently head out in the sun. Physical sunscreen doesn’t need the wait time to start protecting your skin—it works immediately.
• How much is needed to get the job done: For chemical sunscreens, less is more. However, you have to reapply more regularly since it absorbs much quicker than physical sunscreen. Physical sunscreen lasts longer but doesn’t mesh as well with water or sweat.
• How easy it is to apply: Chemical sunscreens can be spread more easily on the skin, while physical sunscreens are often more difficult to blend. They can leave a white cast or chalky look (which is not ideal for people with darker skin tones) and feel heavy on the skin.
• Side effects on the skin: You have an increased risk of irritation using chemical vs physical sunscreen. Chemical sunscreen can also be too much for some people with oily skin, as it comes with the risk of clogging your pores. Physical sunscreen is often better suited for acne-prone, oily or sensitive skin to avoid any irritation.

Dr. King recommends physical sunscreen for its benefits, fewer side effects and the fact that it’s an eco-friendly option. A major reason to reach for a physical sunscreen the fact that it doesn’t harm coral reefs (this is known as being “reef-safe,” while many ingredients found in some chemical sunscreens can have a negative impact on ocean life.

“I recommend physical sunscreens because they block a wide range of UV wavelengths and they are photostable. And there are fewer concerns about their potential adverse effects both to the body and to the environment,” Dr. King suggests.

However, there’s no evidence that it’s harmful to the body other than a few studies done on rats. But if you’re active and tend to sweat a lot, chemical sunscreens may be your go-to for being water-resistant. At the end of the day, it’s really up to you and your preference.

Yup! It doesn’t hurt to reap the benefits of both types at once.

Aside from deciding on chemical or physical sunscreen (or both!), there are a few things to keep in mind when searching for the sunscreen of your dreams. Check out the broad spectrum (you want protection from UV and UVB) and whether or not it’s oil-free, paraben-free and has SPF 30 or higher.

When it comes to application, Dr. King suggests applying one ounce (similar to the size of a shot glass) to the body and a nickel-sized amount to your face. And FYI, there might be some areas you’re not considering.

“Commonly missed areas of application include the hairline, the part, the neck, the tops of the ears, the backs of the hands and the tops of the feet, and the bottoms of the feet if you're in a position where they will be exposed to the sun,” Dr. King pointed out.

It’s also important to apply it every two hours especially after swimming, working out or doing any active activity (unless the product’s label says otherwise). So, what are you waiting for? Grab some sunblock and enjoy the day.