Two sunscreens, one over the other. SPF 30 underneath, SPF 50 on top, and somewhere in the back of your head a small calculator reports SPF 80. That number isn’t real. The problem is that the usual correction, deciding layering is therefore pointless, isn’t real either. Both of those can be wrong at the same…
The 50+ printed on your sunscreen looks like a fact about what’s in the tube. It isn’t. It’s a measurement, taken once, from a product smeared on the backs of ten volunteers in one lab on one day. And in 2020 the whole skincare internet found out what happens when someone pays to take that…
You already scan the SPF number. But right next to it sits something like PA++++, and most people have no idea what those little plus signs are counting. The plus signs are the other half of your sunscreen, and they cover a completely different problem than SPF does. SPF is about burning. PA is about…
Affiliate links below, but they cost you nothing extra. We only point you to what the labels and the science actually back up. You pick up a Korean sunscreen, flip it over, and there it is in tiny print: Water Resistant (40 minutes) or (80 minutes). Most people read that as a loose promise, like…
SPF 100 looks like it should be twice as strong as SPF 50. The number is double, so surely the protection is too. Then you walk into a Korean drugstore, scan the sunscreen shelf, and the biggest number you can find is SPF50+. Not 70, not 90, definitely not 100. So what’s going on? Is…
SPF 50 sounds like it should crush SPF 30. The number is nearly double, so the protection must be too, right? Here’s the part the packaging never spells out: the real gap between them is tiny, and it’s almost certainly not the thing deciding how protected you actually are. So let’s do the honest version…