BALTIMORE (WJZ)—Another energy drink is under fire. More than a dozen deaths are now potentially linked to 5-Hour Energy. The company’s CEO is fighting back.

Meghan McCorkell has more on the caffeine controversy.

The company says a 5-Hour Energy has as much caffeine as a medium Starbucks coffee.

But now the FDA is investigating whether what’s in the bottle could be dangerous.

At the 7-Eleven in Hampden, 5-Hour Energy flies off the shelves.

“A lot of people buy it, and people like to use it,” said manager Ismail Khan.

But new reports indicate that a swig could be hazardous to your health.

According to FDA adverse event reports, 13 deaths over the past four years have mentioned 5-Hour Energy in filings.

The company’s CEO says what’s inside this bottle is safe.

“Amino acids are the main ingredients, and there is some caffeine,” said CEO Manoj Bhargava.

Dr. Gary Kerkvliet with Mercy Medical Center says while the drinks should be safe for most, others could be more susceptible.

“Anything with a stimulant in it, one has to consider ‘Gosh, do I have some underlying heart condition possibly that could be triggered by taking a stimulant?’” Kekvliet said.

Five-Hour Energy is not the first energy drink facing scrutiny. Monster Energy now faces a lawsuit filed by a Maryland family.

Anais Fournier, 14, died from cardiac arrhythmia due to caffeine toxicity.

She’d drank Monster, and doctors say that aggravated a pre-existing heart condition.

Bhargava of 5-Hour Energy says the responsibility lies with doctors.

“If a young person has this heart condition, then the doctor should say you shouldn’t have anything with caffeine in it,” Bhargava said.

Five-Hour Energy does have a label that warns it should not be taken by children under the age of 12.

Some say that’s not enough. The American Academy of Pediatrics warns no one under the age of 18 should consume energy drinks.

The 5-Hour Energy bottle does not reveal the amount of caffeine in the product, and the CEO refused to tell CBS News the exact number of milligrams.