Sales of energy drinks are rising and their brightly coloured cans line the shelves of almost every supermarket or grocery store in the UK. But do brands like Monster, Red Bull and Relentless deliver on their promises?

Listener Syed is a consultant radiologist and says he needs to be on his A-Game in his demanding job. He wants to know if an energy drink would be any better than his usual cup of coffee in helping him stay alert. He's also keen to know more about some of the ingredients they contain - things like taurine, guarana and electrolytes. What exactly do they do? And are energy drinks safe to drink regularly?

Presenter Greg Foot has a thirst for knowledge and speaks to expert dieticians and cardiologists to find out if energy drinks live up to the hype. Are they the best thing since sliced bread - or marketing BS?

PRESENTER: Greg Foot PRODUCER: Simon Hoban