I used to take 6/day. 2 3xday, but I think I have built up a tolerance for stimulants like these. The first bottle I bought I took 2 right before a workout and I almost puked half way through. lol My body seemed to get used to them quickly tho.
You'll need to start with two a day the first day and then go up until like Alpine you get to 6/day (I can only handle 5). As far as "I don't feel anything" that's because you're not supposed to. It doesn't work on your CNS or heart muscle like ephedra products do. That's why you don't get jittery.