This stuff tastes good and holy crap does it work! you only need half a bottle but if you drink the whole thing you will be focused and working out for a few hours for sure! Do not take this 5 hours before bedtime because it can affect your sleep. Also, if you are sensitive to caffeine I would recommend only drinking a quarter to half to see how your body responds to it. I used it as an energy booster to get through my workout but I believe this can be used as a fat lose/appetite suppressant as well.