The product claims to last up to 5 hours. I have super oily skin. When I add this product to my face with a dense powder brush, it lasts for about 3 hours before my face gets really oily again. But if I add this product with a damp sponge (like the BeautyBlender), it lasts much longer; baking the products also extends it the mattifying power.
It differs person to person. I have a very oily T-zone and this only lasts about 2-4 hours. I still prefer this over any drugstore pressed powder I've used. It does control oil very well even when it does wear off. You don't get this slide of oil like you normally would. (Or at least I normally would, haha)
I'm usually only oily in my "T" Zone and it lasts pretty much all 8 hours at school each day. It's not as matte as it was that morning but I wouldn't call my skin oily at the end of the day. Hope this helped. (: