Red Bull is now more likely to give "wiiings" to tired lorry drivers and athletes than vodka-drinking clubbers, with the energy drink more popular in garage forecourts than it is in bars.

Red Bull, the caffeine drink that became notorious as a spirits mixer when it was first launched in the Republic in 1996, said it was outselling Coca-Cola in Esso's On The Run shops.

Across-the-bar sales now account for just 38 per cent of its business, down from 70 per cent in the year of its launch. About one in 10 soft drinks sold across a bar is a Red Bull.

Figures from monitoring firm AC Nielsen show that its sales grew 29 per cent last year, when it sold 53 million cans, compared to a 13 per cent expansion in the sports and energy drinks category and a flat soft drinks market.

Red Bull Ireland's communications manager, Killian Burns, said it had moved away from its "clubber's drink" origins.

"We never marketed it as a mixer, we marketed it as a standalone drink. But people are becoming more aware of the functional benefits of it now," he said.

A 250 ml can of Red Bull contains 80 mg of caffeine - about twice the level of caffeine in a 330 ml can of coke and roughly the same amount as in a cup of filtered coffee. It also contains an organic acid called taurine, which Red Bull claims can "kick-start" the metabolism.

But it is counter-claimed that Vodka Red Bulls, which nightclub patrons use as an energy-booster to stop them from falling asleep on the dance floor, are not healthy because they mix stimulants with a depressant.

The drink, which is still banned in some countries, has a 15 per cent share of the take-home sports and energy market and 3 per cent of the State's €770 million take-home soft drinks, juices and water market. Esso said 9 per cent of its soft drink sales were Red Bull.