Sunscreen vs Sunblock: What’s the Difference?

by Lauren on Mar 28, 2023

sunscreen vs. sunblock: do you know the difference?

You may have heard sunscreen and sunblock being used interchangeably when talking about sun protection. However, the two have completely different ways of protecting skin from the sun’s UV rays.

Whilst both sunscreen and sunblock are popular, you may not be aware of the TYPE of sun protection you are getting when purchasing SPF.

So what IS the difference?

Sunscreen works by filtering unwanted UV light and converting it into heat released from the skin, whereas sunblock acts as a physical barrier between skin and UV rays by reflecting them.

Sunscreen (a.k.a Chemical Sunscreen)

As the name suggests, sunscreen acts as a screen covering the skin and acts as a sponge for incoming UV rays. When the sunscreen and UV rays come into contact, a chemical reaction takes place and UV rays are converted to heat and released from the skin. Chemical sunscreen contains chemicals capable of carrying out this function such as homosalate, oxybenzone and newer active ingredients such as Tinosorb S, which work effectively, but may be unsuitable for sensitive skin.

Chemical sunscreen is effective, but often the chemicals used are unsafe for use when swimming: oxybenzone may react with chlorine in swimming pools. In addition, other chemical ingredients are deemed unsafe for use near reefs due to toxicity towards aquatic wildlife, so it’s always important to think about the usage of the SPF.

Sunblock (a.k.a Physical/Mineral Sunscreen)

As the name also suggests, sunblock physically blocks the sun’s UV rays by forming a barrier and reflecting and scattering the UV rays. It is able to do so thanks to minerals such as zinc oxide and titanium dioxide in its formulation. These minerals may cause the consistency of the sunblock to thicken and cause a white cast, but the formulations work well at providing protection against a broad spectrum of UV rays.

Check the INGREDIENTS

However, it is worth noting that back in 2011, the FDA banned the use of the word sunblock due to the connotation that it provides complete protection from the sun. Therefore, you may not see this in the names of common SPFs.

Overall, the best way to know the type of protection provided by a product is to check the ingredients list. If either zinc oxide or titanium dioxide are included, then the protection will be in the form of a physical sunscreen. If these two ingredients are not included, then the SPF will be a chemical sunscreen.