Mineral vs. Chemical Sunscreen: Both Mostly Absorb UV
The 'physical reflects, chemical absorbs' line you've heard a hundred times is mostly wrong — and the data on so-called mineral products is even messier.
Despite the familiar 'physical reflects, chemical absorbs' framing, recent measurements show both mineral and organic filters protect mainly by absorbing UV; the same analysis found about 34% of products labeled 'mineral-only' contained added UV-absorbing chemical filters.
University researchers studying sunscreen physics note that the reflect-versus-absorb distinction is far smaller than commonly taught, because zinc oxide and titanium dioxide absorb the majority of the UV they block rather than bouncing it away.
Questions we get a lot
So do mineral sunscreens reflect UV or not?
Only to a small degree. Measurement-based research shows zinc oxide and titanium dioxide protect mainly by absorbing UV, with relatively little reflected or scattered. The everyday image of mineral particles acting like tiny mirrors overstates how the chemistry actually works.
Why do some 'mineral' sunscreens contain chemical filters?
An analysis found that around 34% of products marketed as mineral-only also contained added UV-absorbing chemical filters. Manufacturers may include them to improve texture or boost measured protection. It is a reason to read the full active-ingredient list rather than trusting front-label 'mineral' branding.
Does this mean it doesn't matter which type I choose?
The best sunscreen is one you will apply generously and reapply, regardless of category. Both types can deliver strong broad-spectrum protection. Choose based on texture, skin tolerance, and the verified ingredient list rather than the reflect-versus-absorb myth.
r/SkincareAddiction: 'Wait — if my zinc sunscreen mostly absorbs UV too, what's even the point of buying mineral?'