It's different for everyone... it takes about a month for it to completely take effect.
I had 5.5cc for my first, after a few weeks, my hunger died. I have zero appetite anymore. So I'm thinking this is what it is supposed to do! Don't be looking for restriction, look for hunger control. The band will never stop you from eating. My hunger is gone, but I control what I eat. It's harder to overeat with the band (I definitely physically can't eat as much, but I can still eat enough to sabotage myself), I'm just satisfied with less, and with no real appetite you don't really care to over eat.