Health concerns about energy drinks were heightened this week with reports of five deaths possibly linked to Monster Energy drinks.
Caffeine is one of the key ingredients in energy drinks. It can be hard to tell how much they contain. Consumer Reports has just conducted lab tests on dozens of top-selling drinks.
Energy drinks...everybody from Tim Tebow to 50 Cent and Joan Rivers are advertising them. With their Facebook pages and Internet video campaigns, manufacturers specifically target young people.
But Consumer Reports says you have to be careful how much caffeine you drink.
Gayle Williams of Consumer Reports says, "It can quicken your pulse, cause abnormal heart rhythms, keep you from sleeping well, and elevate your blood pressure."
Consumer Reports analyzed the caffeine content of 27 top-selling energy drinks-testing three samples each.
Although some list the amount of caffeine on the package, they're not required to. Consumer Reports found the numbers can be way off.
Williams says, "Some of the energy drinks underestimated the amount of caffeine listed on the label by 20 percent or more."
So how much caffeine do energy drinks contain? In Consumer Reports' tests, it varied widely.
For example, FRS Healthy Energy average 17 milligrams per container.
Red Bull and SK Street Kings Energy around 80. Five-Hour Energy-215 milligrams and 5 Hour Energy Extra Strength-242.
Most healthy adults can consumer up to 400 milligrams of caffeine a day.
Williams says, "So for many people and occasional energy drink is probably okay."
Or you can drink regular coffee. An eight-ounce cup contains roughly 100 milligrams of caffeine.
Consumer and scientific groups have urged the Food and Drug Administration to require companies to disclose caffeine levels, but the agency says it lacks the authority to do so.
Many energy drinks do carry warnings that they are not for children, women who are pregnant or nursing women, or people sensitive to caffeine.