Nowadays I bring my sunscreen with me whenever I go out at daytime, when I expect to be outdoors longer. I’ve been more diligent about applying and reapplying sunscreen after reading several articles about how important this is. Apparently, sunscreen should be applied 30 minutes before sun exposure to allow the ingredients to fully bind to the skin (SkinCancer.org). As for how often it should be reapplied, however, I saw different answers, and basically it depends on a few factors, like the type of sunscreen you’re using and the activities you’ll be doing. Some sources agree that sunscreen should be reapplied at least every two hours. This is also the recommendation of the Australian Academy of Science and the American Academy of Dermatology. But they also noted that sunscreen should be applied more often (say, every hour) when you perspire a lot or go swimming.
I also finally understood what exactly SPF (Sun Protection Factor) meant 😅 The SPF indicates the level of protection the sunscreen has against UVB rays (the ones that cause sunburns). So SPF simply refers to how much longer you can stay in the sun before your skin starts to burn, than when you are not wearing any sunscreen. In my case, I’m using an SPF 50+ PA+++, so the way I understood it, I can stay out in the sun (without getting sunburnt) 50 times longer than if I am not wearing any sunscreen at all. But please correct me if my understanding is wrong 😅
On my Instagram post, a friend of mine commented that a skin ambassador of their company told her that whatever the SPF of the product, you multiply it by 10. She explained, “So if you’re using SPF50, multiply it by 10 you get 500. So you can stay under the sun for 500 minutes before the sun can do damage to your skin.” I was glad she mentioned this because I’ve actually been wondering about exactly how long sunscreens work. What she shared made me curious as to why health organizations would still recommend sunscreen reapplication for around every 2 hours even if sunscreens with SPF 30 or 50 should, theoretically, be able to offer protection for 5 to 8 hours. So I did a bit more reading and found this explanation to make sense: every person’s skin burns at a different rate 😃 For instance, a person with a lighter complexion would burn faster compared to someone who has a darker complexion, since the latter is able to produce more melanin for protection. This rate, however, can also be affected by several other factors, such as the person’s age, diet, the amount of cloud covering the sky, the time of the day s/he’s out in the sun, to name a few. The sun’s rays are stronger at certain times of the day (they’re strongest between 10am and 4pm, according to WebMD, but again this might even also vary depending on where you live. Haha!), so the exact duration of the protection offered by sunscreens is quite hard to determine. Maybe the recommendation of reapplying sunscreen every 2 hours is just the safe number, considering all possible factors 😊
As for the PA+++ part of the label, this one indicates the sunscreen’s level of protection against UVA rays (the ones that cause skin aging). PA stands for “Protection Grade of UVA,” and the more plus signs, the more protection you get. PA+ offers SOME protection against UVA rays, PA++ provides MODERATE protection, PA+++ indicates HIGH protection, and PA++++ means EXTREMELY HIGH protection from UVA rays.
This is just a simplified explanation of how sunscreens generally work. There are many other factors that need to be considered and there’s a lot more to learn if you’re really interested. But for now, at least make sure your sunscreen offers “broad-spectrum” protection, meaning it protects against both UVB and UVA rays. And of course, wear protective clothing, use an umbrella, wear sunglasses, and seek shade when necessary.
I am quite happy with my Cosrx Aloe Soothing Sun Cream (as pictured above) because it’s a high-SPF, broad-spectrum sunscreen that also works as a soothing moisturizer 💚💚💚 I also eventually came to like its very dewy finish because it looks great on my good-skin days. But on my bad skin days, I just minimize the shine with an oil-control powder or an oil-control mist 😁