Are energy drinks bad for you? Photos of stars toting Red Bull are cropping up everywhere. But experts warn that such energy elixirs can be dangerous to your health.(What You're Dying To Know About)(Brief Article)

The latest celeb must-have is far simpler--and cheaper--than a Marc Jacobs bag or a sports car: It's an ever-present can of the energy drink Red Bull. Britney Spears has used it to pep herself up, Demi Moore takes it with her to Hollywood events, and Paris Hilton swears by it whenever she's pulling a late night of partying (which is frequently).

But it isn't just celebs who are chugging Red Bull and other energy drinks. Whether it's to get them through a long day at work or keep them going during a heavy night out, more young women are being drawn by their promises of invigoration. The Web site for Red Bull, for example, claims that the drink "improves endurance, alertness, concentration, and reaction speed."

Launched in the U.S. in 1997, Red Bull sold approximately $525 million in 2003. Its success has spawned copycats, from KMX and 180 to rapper Nelly's signature Pimp Juice and Ice-T's Liquid Ice. Most of these drinks contain hefty doses of sugar and caffeine (or other stimulants), and while these substances are fairly benign when taken alone or in small amounts, experts are now warning that consuming sugar and caffeine together in substantial quantities is a bad idea. "Since these drinks are for sale in retail stores, people assume they are harmless," says Carol Falkowski, research communications director of Hazelden, the famous rehab center in Minnesota, and author of the book Dangerous Drugs. "But they can be addictive and hazardous to your health."

The Slippery Slope

Getting hooked on an energy drink may sound preposterous, but let's look at the science. Take Red Bull for example: One serving contains 27 grams of sugar and 80 milligrams of caffeine. (The third major ingredient is 1,000 milligrams of the amino acid taurine; the effects of this high a dosage are unknown.) Twenty-seven grams of sugar is about the same amount as is in a candy bar, and it causes the glucose levels in your blood to spike and then, within an hour or so, crash, creating a roller-coaster effect.

Then there's the caffeine. It's a central nervous system stimulant, and on caffeine's command, your body pumps out adrenaline, which heightens alertness. The 80 milligrams in one can of Bed Bull is about the stone as you'd find in a cup of brewed coffee. However, people sometimes don't finish a full serving of coffee in one sitting because it gets cold. Also, a cup of joe, even when you add sugar, is much more bitter than Red Bull, so you're less prone to guzzling it. The double whammy of sugar and caffeine offers a brief but powerful high, which is what makes the combination potentially dangerous. "People get hooked on the high," Falkowski explains. "Anytime you become accustomed to a mood swing, whether it's through marijuana or an energy drink, you increase your risk of developing a habit."

Just ask 24-year-old Alison * from Boston. She's been drinking anywhere from two to four energy drinks every day for more than a year, relying on them to rev her up whenever she's flagging in the office. "Red Bull will flick a switch in my head and launch me into a motivational state every afternoon," she admits. "It's even replaced my morning latte. And I'm always shaking the can for the last drops when I'm done. At the end of one can, I want more."