It’s 7:40 in the evening. The sun went down half an hour ago, you’re at the bathroom sink, and some small voice asks whether you were supposed to top up your sunscreen after lunch. Somewhere along the way the advice became every day, all day, indoors too, screens included. It started as a real sentence…
Your weather app has a UV number in it right now, and probably a color behind it. The color has five settings. The instructions behind the color have three. The short version: here’s the whole UV index sunscreen guide in one line. The five band scale you know, low through extreme, is a reporting scheme…
In 2019 a research team reviewed everything published on sunscreen and vitamin D. In 2025 the same team ran their own trial and got a different number. The short version: the question of sunscreen and vitamin D deficiency got a new answer last year, and it’s a small one rather than a scary one. In…
People pack differently for a desert trip than for a beach one, and they usually pack the wrong thing. The instinct is to reach for something more water-resistant, or a higher number. Neither is the thing that fails you in dry air. What fails is the surface you’re putting it on. The short version: picking…
The most common way sunscreen fails in the tropics isn’t the one people plan for. It isn’t washing off in the sea, and it isn’t sweating away on a hike. It’s that the stuff feels so unpleasant by 10am that you stop putting it on. An SPF 50 you skipped is an SPF 0. The…
The sky is flat grey, the sun is nowhere in sight, and skipping sunscreen feels like the obvious call. It isn’t. Clouds block a lot less UV than they look like they should, and the ray that ages your skin barely notices them. The real question is whether you need a cloudy day sunscreen at…
At 8 a.m. your face was fresh and powdery. By noon, your T-zone is a mirror. If you have oily skin, you know this timeline by heart, and the usual conclusion is “I need a new sunscreen.” Probably not. This post assumes you already own a decent one, and shows you how to keep Korean…