The New Power Brew: Do Energy Drinks Really Work?

Do the Ingredients in Your Energy Drink Work?

The real scoop on whether the vitamins, minerals, and dietary supplements in your energy drink really work:

Ingredient: Guarana

Claim: Improves alertness and physical performance; reduces fatigue

The science: "Caffeine is a component of guarana, which is why it can provide similar benefits," says Kevin Clauson of Nova Southeastern University College of Pharmacy in Fort Lauderdale, Florida. But since the amount of caffeine varies from 2 to 8 percent, it's hard to determine exactly how big a boost you'll get.

Ingredient: B vitamins

Claim: Boost energy and metabolism

The science: "B vitamins help convert food into energy," says Nancy Clark, RD. "However, only a person who is B deficient will get any benefit, and it would take regular supplementation." And studies to date have reported that B vitamins have no effect on performance, a 2010 review in the journal Physician and Sportsmedicine found.

Ingredient: Taurine

Claim: Lessens exercise-induced DNA damage, thereby improving exercise capacity and performance

The science: Few scientifically accepted studies confirm taurine's performance enhancing powers.

Ingredient: Ginseng

Claim: Increases stamina, energy, and mental focus

The science: "There are many types of ginseng, and from what the literature shows, only Panax provides the full range of these benefits," Clauson says. "You need anywhere from 100 to 2,000 milligrams per day to see any real benefits." Most energy drinks contain much less.