[Product Question] - Are near/expired but unopened skin care products (creams and CM) still effective?

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because i was lazy and stupid and didn't realize how bad I was, i have managed to sadly create a stash of skincare products (there were not supposed to be a stash, i was supposed to use them). My question is whether they will be effective or not (i think i'll still use them even if they aren't because overall they're worth quite a bit of money) if I use them past expiration date BUT they are unopened (i.e. Expiring in 09/17 but haven't been open at all).
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Submitted by balne