"Red Bull gives you wings,” asserts one TV spot. Some energy drinks sport suggestive names like Amp and Battery, others are more matter-of-fact, such as 5-Hour Energy, which comes in “shots.”

But whether they promise a boost or a buzz, what energy drinks deliver is no great shakes, according to exercise physiologist and dietitian Kara Mitchell, RD, who coordinates both the fitness and nutrition programs at Duke Health & Fitness Center.

“The central ingredients in most of these drinks are caffeine and sugar,” says Mitchell.

Forget those B vitamins some drinks tout as their secret weapon. “There is zero research supporting that these will boost energy -- it’s just the caffeine.”

The herbal ingredient guarana, commonly added to energy drinks, also contains caffeine.

A typical cup of coffee has 80 to 135 milligrams of caffeine, but some energy drinks contain two or three times that amount.

When you consider that most fans don’t stop at one little bullet can, but consume several a day, you can understand why energy drinks make nutrition experts a little nervous.

“A little caffeine is not that bad for most people, but you just don’t need that amount in your diet,” says Mitchell, who notes that heavy caffeine consumption increases irritability, raises blood pressure, and heightens the risk of irregular heart rhythms.

“You may also be masking issues like fatigue, not getting enough sleep, that really need to be addressed.”

Those seeking to enhance a workout may opt for sports drinks like Gatorade or Powerade.

They’re a safer alternative to energy drinks because they aren’t caffeinated, says Mitchell, but she recommends sticking to the lower-calorie versions and she notes that most people simply don’t need them.

“Sports drinks are meant for athletes to replenish electrolytes. If you’re sweating longer than an hour, these might be a good resource. Some enjoy the drink because it offers hydration with flavor. I have few concerns with people drinking these kinds of beverages, but you should be aware of the sugar and calorie content in the beverage you choose.”

Are vitamin-fortified water and protein drinks worth the price? Read the rest of the article on DukeHealth.org.