Do popular sports products actually help?
Consumers could be wasting their money on sports drinks, protein shakes and high-end trainers.
That's according to a new joint investigation by the BBC's Panorama programme and the British Medical Journal into the performance-enhancing claims of some products.
Shelley Jofre reports on the new study that aims to separate the science from the sell when it comes to some of the country's most popular sports products.
Panorama: The Truth About Sports Products, BBC One, Thursday, 19 July at 20:00 BST and then available in the UK on the BBC iPlayer.