It has been around ages, but is available in all sorts of 'dosages' if that makes sense, so if you do get it, make sure it's the best quality you can afford. Me personally, I think it's all psychological? Fibre-bulking drinks make you 'feel' full at a fraction of the cost!
And again, do you want to be reliant on pills for the rest of your life to control your appetite if you're just eating the 'wrong' foods?