Just like energy drinks and antioxidant-rich juices, like pomegranate, have exploded in popularity, the most recent drink du jour to hit the specialty beverage category by storm is caffeinated water. And while these new thirst quenchers may give you an energy bump without the coffee stains, you may be wondering—how good is it for you really?COLUMN: Are Energy Drinks Safe? Brands such as Water Joe, Avitae, Fyxx Hybrid, Element and Krank20 all claim to deliver the well-known benefits of drinking water along with being sugar- and carb-free—paired with the buzzy jolt of a cup of Joe. And that’s precisely the problem, according to Karen Congro, R.D., nutritionist and director of the Wellness for Life Program at The Brooklyn Hospital Center in New York City. “The dehydrating effects of caffeine cancel out the hydration benefits.”But studies show that really depends on how much caffeine you’re getting. Although medical and nutrition experts have warned about caffeine’s diuretic effect for years, research shows you would need to down a lot of caffeine—500 milligrams or more than five cups—to dehydrate yourself. In other words, drinking a cup or two of coffee isn’t going to leave you parched.What’s more, caffeine has some noteworthy health benefits, including decreasing the risk of Alzheimer’s and Parkinson’s disease, according to YouBeauty co-founder Michael Roizen, M.D. Case in point: Research published in the Journal of Alzheimer’s Disease found substantial evidence that suggests caffeine may slow the onset of Alzheimer’s disease.Congro concedes that there’s not much harm in consuming one or two cups of coffee per day—a cup of coffee can range from 50 to 95 milligrams of caffeine—but she pointed out that it’s easy to go overboard with caffeine-loaded water. While most of the caffeinated water brands claim that their beverages provide about the same amount of caffeine found in a cup of coffee, some—like Water Joe—are sold in bottles that contain 70 and even 120 milligrams of caffeine.COLUMN: Drinking Coffee May Squelch Skin Cancer“The problem is that drinking water with caffeine in it can be kind of misleading,” she says. That’s because people tend to sip their hot coffee, but can easily chug copious amounts when it comes to caffeinated water. “You could really go crazy with the caffeine which, in this theoretical case, can possibly lead to restlessness, insomnia, stomach issues and muscle tremors. Too much caffeine can even raise blood pressure and affect your heartbeat.”Congro strongly cautions that pregnant women and children should avoid caffeine. But for the die-hard caffeine drinkers out there, she recommends sticking to plain old tea and coffee to get your fix. “They have wonderful health benefits, like antioxidants,” she says.MORE: Coffee vs. Tea—Which One Is Better For You?