I think the main problem with all these fad supplements, pills etc is that, even if they work, you can't stay on them forever, and as soon as you stop taking them the weight piles on again because you haven't actually changed your way of eating in a sustainable way.
I'm sure people say 'I just need to lose so many lbs or stones, then I'll be able to carry on by myself' but it really doesn't work out like that.
The ONLY way to lose weight and keep it off is to change the way you eat, because the way you ate before is what caused your weight loss in the first place, so you can't 'go back' to normal after dieting, you have to change what's 'normal'.