A group of doctors in Nova Scotia are recommending a ban on the sale of energy drinks to anyone under the age of 19 and their concerns are intensified by a recent U.S. Food and Drug Administration investigation into 13 deaths possibly linked to so-called energy shots.

The U.S. agency has received 92 reports that cite illnesses, hospitalizations and deaths after consumption of a product marketed as 5-Hour Energy. The U.S. Food and Drug Administration has also received reports that cited the highly caffeinated Monster Energy Drink in five deaths and one non-fatal heart attack.

The 5-Hour Energy label says it shouldn't be consumed by anyone under the age of 14.

"These are products which are very available to youth at the present time and there are significant medical concerns about their use and overuse," said Dr. John Finley, president of Doctors Nova Scotia.

His group is calling on an age restriction for caffeinated energy drinks.

The shot's small size can also be dangerous to consumers with underlying conditions because it's easier to take several of them or mix them with alcohol. Though it comes in liquid form, the 5-Hour Energy shot is marketed not as a drink, but as a dietary supplement.

Elaine Lutz, a spokeswoman for Michigan-based Living Essentials, LLC — which makes 5-Hour Energy — said the company is not aware of any deaths proven to have been caused by their product. She said the company's website advises consumers to drink no more than two bottles of the shots per day, spaced several hours apart and for new consumers to drink half a bottle to start.

Jonathan McDonald, a student with Dalhousie University's law school, is a fan of 5-Hour Energy but says he's considering the effects carefully.

"It's definitely something that discourages me from taking it, having to read all these bad stories and all the side effects that different people are experiencing," he said.

Health Canada recommends adults have no more than 400 mg of caffeine per day, which equals roughly two of the 5-Hour Energy drinks.

Finley said too much caffeine can result in agitation, anxiety, sleepless nights and possibly heart palpitations.

With files from The Canadian Press