I'm running an epi cycle now. 2 weeks in and it feels like it always does. And the epi I'm using is 12 months past the use by date on the bottle. Bottle wasn't sealed either, as I'd run a cycle with it 12 months ago.
There are a bunch of threads here about use by dates and why they are so short. My experience is that the stuff works just fine well after the dates.
No science behind this comment. Just know that it works for me.
Stocked up on mdrol etc ages ago and that all still works as before too.