Health Canada is investigating a popular energy drink it approved for sale less than six months ago.

Red Bull is all the rage among club-goers and energy junkies in Canada. However, the drink has been banned in France and Denmark.

Health Canada says it's now looking into three reports of adverse health effects from consuming the drink.

"The whole situation is under review right now," said Health Canada's Natalie Lalonde, opening up the possibility that the drink could be banned in this country as well.

At about $3.50 for a can, Red Bull is an expensive drink. But the owner of a downtown Toronto variety store says Red Bull quickly replaced Coca-Cola as his number one seller.

The can may be small, but it packs a big caffeine punch. One serving has the same amount of the stimulant as a large Starbucks coffee.

Young people report different reactions after trying the drink. "It builds up your energy to be more active," said TJ Ramos.

Daryl Golden described Red Bull as "just kind of a sugary alcoholic-type drink."

Kieran Meyn said he "felt a little more energized," but said Red Bull was "nothing special."

Ciaran Persad did exactly what you're not supposed to do with Red Bull -- he drank it while working out.

"A lot of strange things happened actually," Persad said. "I got some strange muscle twitches in my arm."

The University of Toronto's Ahmed el-Sohemy says he's not surprised. A gene-diet interaction specialist, el-Sohemy has been studying the effects of caffeine on the human body for years.

"I think it's dangerous to market a product as a sports drink that has these ingredients in it," he said.

Red Bull is the best-selling energy drink in Europe, where retailers sell 1.6 billion cans each year. But, Canadian consumers will have to wait for the results of the Health Canada review to find out whether the drink will stay on the shelves in this country as well.

With files from CFTO's Paul Bliss