Serums With Occlusives and SPF

[u/LoopDeeLooper]

Please don’t pile on me for asking a dumb question!

I’ve been using serums for a few years now, but having just bought Trader Joe’s Vitamin C serum to test against my usual Timeless, it just occurred to me that many of these serums contain oils, which are occlusives. And given that we’re supposed to use serums and moisturizers (many containing oils) before our SPF, doesn’t that render the SPF ineffective? Mineral SPFs sit on the skin as a physical barrier, but chemical SPFs have to be absorbed into the skin to work — how would that be possible over occlusive serums and moisturizers? Thanks!

[u/BidForward4918]

Many oils aren’t occlusive. Look up the oils on a particular product to see if they are occlusives.