[Sun Care] For a sunscreen to maintain the integrity of its’ water resistant or sweat resistant claim, does it have to be applied to bare skin, or can it be applied over top of other products?

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I was thinking about this earlier today before going to the gym. I sweat loads whenever I’m active, and for this reason I seek out sweat or water resistant sunscreens. However, I also thought about the fact that these film forming, resilient sunscreens are going over the top of water soluble, basic moisturizers and serums and whatever else that probably easily lift away with sweat or water. If the sunscreen has formed a film on top of these, and then you sweat and those underneath products start to migrate and lift, then isn’t the sunscreen being taken away with it..?I haven’t seen this question in this sub before, so I figured I’d ask. I’m not certain if we have studies to back this up, but I’m so curious! Thank you!
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Submitted by IamDonatella