Ever heard “Chemical sunscreens absorb UV rays, while mineral sunscreen act like a shield, defending your skin”? This statement is usually accompanied by a simple picture of your skin, the sun, and UV rays bouncing happily off your body, no harm done.

But maybe you’ve also heard scientists calling this out as false. And the truth is, zinc oxide and titanium dioxide do primarily function by absorbing UV rays, just like chemical sunscreens; only a small portion of UV radiation is reflected away from your skin by these physical UV filters.

So what gives? Well, here’s the actual difference:

Whereas physical UV filters Zinc Oxide and Titanium Dioxide remain on the outer layers of your skin, most common chemical UV filters absorb into your bloodstream. This systemic absorption has been studied in detail. Here’s what researchers have found:

·       Oxybenzone, Octinoxate, Octocrylene, Octisalate and Avobenzone have found in human blood at rates well above the FDA’s cutoff for safe exposure (Walters 1997, Hayden 2005, Matta 2019 & 2020).

·       Oxybenzone, Octinoxate, Octocrylene and 4-MBC have been found in breast milk (Schlumpf 2010).

·       Benzophenones (look for Oxybenzone or Benzophenone-3) and Avobenzone have also been found in amniotic fluid and/or umbilical cord blood, meaning these filters cross the placental barrier from mother to child (Krause 2017, Sunyer-Caldu 2023).

In contrast, Zinc Oxide has been declared Safe and Effective (GRASE) by the US FDA because, in their words, there is "substantial evidence that zinc oxide... does not penetrate into or through human skin to any great extent and, to the extent any de minimis {minimal} penetration occurs, does not result in adverse health effects.”

So yes, Zinc Oxide absorbs UV rays, but it will not end up your body, or in your children’s bodies. It stays in the outer layers of your epidermis, providing you broad spectrum protection you from UVA and UVB rays.

Sounds like a super shield to us!