I find this great when playing sport. Badminton, squash and cricket. It appears to give me extra energy when flagging, as an energy drink. I have a bottle of this and a bottle of water separate.
It is not available in the supermarkets or any shops round here, and at amazon is cheap at £17 for 24 bottles, and usually comes in a few days and is well packed, though once the bottles were broken at the local couriers and had to be reordered so took longer.