What’s the Difference Between Physical and Chemical Sunscreen?

Diving into the two categories of sunscreen and how to properly apply them.

Anya Gipsov

Product at Atolla

Anya Gipsov

Anya is a graduate student at Carnegie Mellon University, focused on product development at the intersection of beauty and biotechnology.



Skin Science

We’ve been hearing a lot of buzz about sunscreen lately, so we wanted to clear up some of the basics. Today in the Skin Lab, we’re talking about the two categories of sunscreen: physical and chemical. 

When it comes down to it, the difference is in the ingredients: 

  • Physical sunscreens use mineral ingredients such as titanium dioxide or zinc oxide to deflect UV rays. 
  • Chemical sunscreens use a cocktail of ingredients such as avobenzone, octinoxate, and octisalate to provide protection across the UV light spectrum. While the FDA is still doing research on some of these ingredients, they are regarded as safe to use in the low concentrations used in sunscreen. 

For both types of sunscreen, look for the word “non-comedogenic” on the label: this means the sunscreen should be less likely to clog pores. 

The bottom line is you can use either, and the texture or type is up to your preference. In the end, any sunscreen is better than no sunscreen!

Tips for sunscreen application:

  • All sunscreens eventually stop working no matter the SPF or quantity you put on, so make sure you reapply every two hours (especially after sweating, swimming, and drying off).
  • Unlike physical sunscreens, chemical sunscreens need around 20-30 minutes to absorb the active ingredients, so they should be applied before going outside.
  • Physical sunscreens can sometimes leave a white cast on the face when applied. If your sunscreen does this, try rubbing it between your hands first to emulsify it.
  • Follow the “shot glass rule” when applying sunscreen: one full shot of sunscreen is the right amount to cover your body. For your face, that scales to about half a teaspoon.
  • Whether you tan or burn in the sun, both are signs of cellular damage. You should wear sunscreen no matter your skin tone!
  • The active ingredients in your Atolla serum might make you more sensitive to the sun. If they do, we’ll let you know in the packaging for your serum — look out for a sheet that says SUNBURN ALERT.
Look out for the Sunburn Alert in the packaging of your Atolla serum.

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