You’ve probably seen the little black capsules in the supplement aisle of your nearest supermarket or the thick, grayish masks next to the face wash at the drugstore. Maybe you’ve noticed bottles filled with an inky-looking liquid by the fruit smoothies and green drinks at the juice bar. What’s it all about? Two words: activated charcoal. Made from the charred remains of wood, coconut shells, or coal—which have been heated at high temperatures to expand their surface area—activated charcoal is popping up in everything from lemonade to deodorant. Wellness gurus wax poetic about its ability to rid the body of toxic chemicals thanks to its absorptive power. To put the superpower of its tiny pores into perspective: “One tablespoon of activated charcoal has the same surface area as a football field,” says Kent Olson M.D., clinical professor of medicine and pharmacy at the University of California, San Francisco. But is this just the dark side of a growing industry that can be big on promises and low on science? Here, experts debate the pluses and minuses of charcoal mania.

“CHARCOAL DOESN’T KNOW THE DIFFERENCE BETWEEN A TOXIN AND A NUTRIENT, SO IT COULD POTENTIALLY ABSORB TH I N G S YOUR BODY NEEDS .” — K E N T O L S O N , M . D.

The claim IT ABSORBS TOXINS.

Anyone who’s visited the hospital after accidentally ingesting toxins has seen that thick black sludge docs used to treat acute poisoning. It’s a mix of, you guessed it, activated charcoal. Some experts think it can do more outside of the ER. “As an occasional digestive cleanse, activated charcoal can bind to and eliminate pesticides from the foods we eat, chemicals in the water we drink, and mold we may breathe in,” says Los Angeles-based holistic nutritionist Elissa Goodman, who has developed organic cleanse plans for star clients like Kate Hudson. But the research is scant, and taking charcoal pills or drinking the black juice may interfere with the absorption of other medications you’re using. That’s why some docs want you to pass. “Charcoal doesn’t know the difference between a toxin and a nutrient, so it could potentially absorb things your body needs,” says Dr. Olson.

The claim IT WHITENS TEETH.

YouTube videos of people brushing with charcoal powder mixed with water or coconut oil are racking up millions of views. Proponents say it’s a more natural alternative to traditional whiteners, which use hydrogen peroxide (or a form of it called carbamide peroxide) to blast away discoloring. “The charcoal binds to surface stains to remove them,” Goodman says. Dentists agree that you may see results, but still advise caution. “Charcoal’s abrasiveness can remove stains from the surface of your teeth, but it can also permanently stain porcelain crowns,” says William Graves, D.M.D., an associate professor in the Department of Oral Surgery at Texas Tech Medical School.

The claim IT DECONGESTS CLOGGED PORES.

Black masks, black cleansers, black face scrubs, black soap—you’ll find them all lining store shelves these days. Natural beauty enthusiasts and dermatologists alike rave about their ability to remove oil and dirt. “In this case, activated charcoal works by adsorption—pulling gunk out of pores for clearer, smoother-looking skin,” says Joshua Zeichner, M.D., director of cosmetic and clinical research at Mount Sinai Hospital in New York. “There’s not much research on its effectiveness, but I’ve seen that it can remove oil, dirt, and particulate matter. Is it any better than traditional clay masks? Who knows.”

The claim IT RELIEVES DIGESTIVE AILMENTS.

Several small studies show that activated charcoal can relieve the symptoms of dyspepsia—bloating, nausea, gas—when ingested. “We’re just not sure if it’s superior to other commonly used over-the-counter medications for gastric distress,” says Maged Rizk, M.D., a gastroenterologist with the Cleveland Clinic. If you want to try charcoal to treat gas or bloating, Dr. Rizk suggests a 25- to 100-gram dosage. Most supplements exceed that amount, so it may be better to buy the powder and measure it out yourself. “I certainly would not recommend using it regularly though,” he says.

The claim IT NEUTRALIZES BODY ODOR.

With claims of a connection between the aluminum commonly found in antiperspirants and certain forms of cancer continuing to abound (most docs say there’s absolutely no cause for concern), consumers are continuing to turn to more natural, aluminum-free alternatives. Enter activated charcoal deodorants. Devotees like nutritionist Goodman say the charcoal molecules latch onto odor-causing bacteria (notice a theme?) before they can proliferate and make you stink. Dermatologists are skeptical. “There’s no research that I’m aware of that shows that activated charcoal has any ability to prevent body odor,” Dr. Zeichner says. “And the only ingredient currently approved to prevent excessive sweating is aluminum salt, which is safe to use.”

Is charcoal right for you?

Though it’s generally considered benign and safe to use occasionally, consult with your doctor before taking activated charcoal to make sure it won’t interfere with any medications you’re on. The Mayo Clinic currently lists more than 30 drugs that may interact significantly with oral activated charcoal, and fatalities have been reported when the powder has been inhaled. For this reason, Goodman recommends taking charcoal first thing in the morning—and not regularly for any considerable length of time. She also cautions that not all activated charcoal is the same: “I recommend using a charcoal derived from coconut, so it’s important to read the labels carefully.” It’s available in pill and powder form, so if you’re using a powdered type keep in mind Dr. Rizk’s dosage recommendation of no more than 300 grams at a time.