It’s true. And like all drugs, sunscreen is dose-dependent. So knowing how much to apply to actually achieve the promised number on the bottle is key.
You need to cover two fingers (insert photo) to get the correct dose. This is approximately ⅓ teaspoon unless you have big hands (therefore a larger face) and then you need even more coverage. That cute little dot that you mix with lotion or makeup doesnt work — you need a full two fingers’ worth. And you need to reapply as well. And layering products doesn't double protection. I’ve actually had clients say “Well I mix my 15 spf with some of my tinted moisturizer that also has 15 so I wear SPF 30.” That’s not how it works! The good news is, there are so many different excellent sunscreens to choose from. Just make sure you are wearing enough!