Unfortunately, dark circles are caused by the thinness of the skin around your eyes, and no amount of cream or magical potion will take them away. Not enough sleep will cause them to look even worse, but once you have them - and I'm assuming you've always had them to some extent - you will always have them. I've had dark circles under my eyes since I was old enough to spell 'concealer'
but have noticed since I've gotten older that they've gotten worse, probably because my skin is changing some with age and it's becoming thinner than it used to be. Hence, the circles look even darker. The only thing that 'works' at getting rid of them is a very good hand at make-up.