It helps you concentrate. It can stop you feeling tired. It can enhance your performance. But it's one of the few drugs in which a heady ingestion won't bother the drug testers. On Wednesday, England's lethargic performance against Poland was blamed on some players having taken caffeine tablets before the rained-off attempt to play the game on Tuesday evening. Subsequently – having not run it out of their system with a 90-minutes game – they were said to have struggled to sleep.
Most people's experience of caffeine pills probably comes from nights of cramming at university, using the likes of Bayer's ProPlus, which is heavily marketed to students. As well as adverts, which take solid aim at term-nine crammers, its website even features a downloadable revision guide featuring a giant ProPlus logo.
Head to The Student Room and you'll see dozens of archived discussions about the merits of using the pills as a revision aid. These tend to be a bit more sensible than Facebook groups with names like "off my nut on Red Bull and ProPlus" with most users on warning others that, rather than topping up their blood with hundreds of miligrams of caffeine, it might be more sensible to rethink one's revision schedule and get some sleep.
One ProPlus tablet has 50mg of caffeine in it – equivalent to half of a cup of coffee. The Food Standards Agency suggests adults should consume no more than 400mg per day, making a boost from a ProPlus fine. But too much caffeine can be deadly. Indeed, in 2002 a Cardiff student's death was ruled as a suicide after overdosing on them.
England's players and other professional sportspeople's intake will be carefully controlled by team doctors, not just because of the dangers of taking too much (though cyclist Taylor Phinney told Velo Nation this week about other cyclists picking up "finish bottles, which are just bottles of crushed up caffeine pills and painkillers" to ensure a frantic end to a race) but also because excessive amounts are monitored by the World Anti-Doping Agency. WADA obviously can't outlaw the drug as it's so prevalent in food and drink.
Night shift-workers, truck-drivers and students might have less tabs kept on them – but it does provide one unlikely link between bedsitland and the superfit millionaires of English football.