They're everywhere these days, but what does the latest scientific research on them reveal?

Michael reveals what e-cigarettes are really doing to your health.

• Are they really better for you than cigarettes?
• What is actually in them?
• Is passive vapour harmful?
• And can they really stop you from smoking?

Michael meets some of the scientists around the world studying them, asks a group of volunteers to try to give up smoking regular cigarettes using them, and even takes up 'vaping' himself, smoking an e-cigarette every day for a month to see the effects on his own health - no easy task for such a committed non-smoker.