My 75mg tabs are instant release and I take them all in the morning because I do get the slight stimulant effect from them. It works as an appetite suppressant for me, which is nice as I need to lose some weight. I have lost about 18 pounds and need to lose 20 more. Because of my substance abuse history, wellbutrin almost make me feel guilty because it is a "happy pill" of sorts. But it makes me better able to function instead of less. And it makes me less likely to drink or use.