I am taking it at the moment. I noticed it working pretty much straight away and DD2's general mood improved very quickly (as she was no longer hungry all the time). I am taking 3 or 4 a day, my GP said it was the kind of thing you take as needed so it varies. TBH I haven't heard of taking it for 16 days then stopping, anecdotal evidence I have heard is of people stopping and their supply going back to crap soon after, but that could be just the people I know?