SAN ANTONIO -

A large canned energy drink in hand, San Antonio College student Jennifer Moore was heading to class. 

"It doesn't really scare me," she said of the government probe into reports of 13 deaths of people who took energy shots marketed as 5-Hour Energy.

As a busy student who can sometimes struggle to stay alert in class, Moore said she has tried several energy products, including 5-Hour Energy.

"I think it really helps  me stay focused," she said. "Sometimes, you can get a little drowsy in class."

Now the tiny 1.93-ounce shot of caffeine, vitamins and a substance called taurine, is the focus of a Food and Drug Administration probe into reports of 13 deaths and 33 hospitalizations over the past four years.

News of the reports was cause for worry for Adrina Jaso, who said he's tried the product.

"Who wants to die, you know? If you take it and feel bad, don't do it again."

Student Jonathan Galvan said his first experience with the product  was his last.

"I drank it and I got really nauseated and threw up," he said.  "A lot of students, they're dealing with work and they  use these things to pump them up, and they don't realize how dangerous they can be."

The label on the product does not indicate how much caffeine is in it.  However, a Consumer Reports test found one bottle has 215 mg of caffeine, approximately the same as two cups of coffee.

The company maintains the product is intended for busy adults. The label says it's not for people under the age of 12.