That time I realized my sunscreen was basically useless for real life

I always thought applying sunscreen was pretty straightforward. Like, just slather it on and you’re good to go. I mean, I knew about the SPF numbers and PA ratings, and I always tried to pick something with a decent SPF, like 50+. But then I started noticing things. Like, my skin still getting a bit tanned even when I thought I was protected.

I live in an apartment that gets a lot of sun, especially in the afternoon. The windows are big, and I spend a good chunk of time just chilling or working near them. One day, I was reading something online about how even indoors, you should wear sunscreen. It mentioned something about SPF 15-30 and PA++ being enough for indoor use. That felt… low? I usually go for SPF 50+ just to be safe. The article also said you need to apply about a 500-won coin size amount. That’s actually a lot, more than I thought. And if you sweat a lot or your skin gets oily, you have to reapply. Okay, that makes sense. I do tend to get a bit shiny by the end of the day, especially around my nose and forehead.

So, I started being more mindful. I bought this big tube of sunscreen, probably around 100ml, because I figured if I’m supposed to use that much, I’ll go through it fast. It wasn’t super expensive, maybe around 20,000 KRW? It was a generic brand, nothing fancy, just something I grabbed at the drugstore. It was okay, not too sticky, and didn’t leave a crazy white cast. But applying a full 500-won coin’s worth every few hours? That felt like a chore. And I still felt like I was getting some sun exposure through the window.

Then I read about the ‘2-5-2 rule’ for sunscreen. It basically says SPF 30 means you can theoretically be exposed to the same level of UV for 300 minutes (10 minutes x 30). But that’s only if nothing interferes. And it also strongly suggests reapplying every 2-3 hours because sweat and friction reduce the effectiveness. This is where it started to feel complicated. How do you even track that when you’re just going about your day? I’d apply it in the morning, then maybe once more if I went out. But sitting by the window all afternoon? I wasn’t reapplying every couple of hours. The article also said that higher SPF and more ‘+’ signs mean more UV filtering ingredients, which can sometimes irritate sensitive skin. That was a bit of a worry since my skin can be a bit temperamental.

I also saw some mentions of Korean sunscreens doing well internationally because they’re formulated to be less irritating and not leave a white cast, even for daily use. One article talked about how in South Africa, K-beauty sunscreens are popular because they’re not sticky and don’t sting the eyes. That’s a big deal for me – I hate that stinging feeling. It also mentioned that for daily use, SPF 30 or higher is recommended. But for long hours outdoors, SPF 50 is better. It just seemed like there were so many factors. Was SPF 50+ enough if I was sitting by a sunny window for hours? Or did I need something even higher? The idea of using a sunscreen with, say, 81.2% skincare ingredients, like one brand called Noily, also popped up. That sounded nice, less like just a shield and more like a treatment, but I wasn’t sure if it offered enough protection on its own, especially since it was SPF 50+ and PA+++. I’m still not entirely sure if the amount I’m using, and the timing of reapplication, is truly cutting it for all-day, indoor sun exposure. It feels like I’m doing more than before, but the effectiveness is still a bit of a question mark in my mind.