Charcoal toothpaste is the latest Internet-fueled trend, promoted as a natural way to brighten your smile and detoxify your mouth. If your first response is, Why would I want to chomp down on some charcoal?, hold onto that thought. You are not alone. Dentists, even holistic dentists who embrace natural and complementary treatments, are not rushing to endorse this tooth-cleansing treatment.

Is the fad a…whitewash? Or is there some science behind the idea of brushing your teeth with a jet black toothpaste? Open wide, we’re going to take a closer look…

CHARCOAL, THE TOXIN MAGNET

Activated charcoal, a form of carbon that is processed to have small absorbent pores, has well-established medical uses. It absorbs a wide variety of compounds, including many toxins. It’s an essential part of many hospitals’ toolkits to treat accidental poisoning, food-borne illnesses resulting in severe diarrhea, and drug overdoses. (It’s not always the best choice, though, so if you think you’ve been poisoned, call Poison Control at 800-222-1222 first.)

How did activated charcoal get into toothpaste? The concept is that activated charcoal in toothpaste can absorb toxins in the mouth, including bacteria that cause bad breath and gum disease—and the compounds on the teeth that cause stains. The practice of using charcoal to brush teeth actually goes back to ancient Greece and has been found in many parts of the world.

Why not revive this ancient practice? One modern reason is that there’s been limited research on its safety and effectiveness. Because of charcoal toothpaste’s growing popularity, the American Dental Association (ADA) published a scientific literature review in its peer-reviewed journal. Researchers found little evidence that charcoal reduced bacteria or prevented cavities or that it had any cosmetic benefits. They found that there wasn’t enough research to show that it’s safe. They even pointed to some possible carcinogenic ingredients in charcoal and in clay that are found in some of these toothpastes.

To be sure, a lack of evidence doesn’t necessarily mean something isn’t effective. It just means it hasn’t been studied much. But there is something that is well-known about activated charcoal that gives pause even among holistic dental experts who enthusiastically use certain products that aren’t endorsed by the ADA—it’s very abrasive. That means it can damage tooth enamel, the hard, semi-translucent material that protects your teeth. Once tooth enamel is gone, it’s gone forever. Charcoal can also hurt your gums.

If you wear the enamel away, the dentin layers that are right underneath are going to show up more—and they are yellower. Result: With charcoal toothpaste you might get a quick whitening effect as the charcoal rubs away surface stains, but it could be short lived—and leave your teeth with less enamel to protect them from damage, including cavities.

A BETTER WAY TO WHITEN TEETH

If you’re looking for whiter teeth, the most effective and long-lasting whitening method is using custom trays made by a dentist. Over-the-counter whitening strips are another alternative.

What about charcoal toothpaste for removing bacteria and possibly removing toxins? This has not been substantiated!

Most people don’t need help in that arena—saliva has antibacterial properties. (If you have dry mouth and too little saliva, you can protect your teeth with a toothpaste that contains fluoride.)

Scientifically, charcoal toothpaste sounds crazy to me, and I believe in complementary treatments. If you still want to try it—which I do not recommend—use it no more than once a week or every other week. Use a soft toothbrush, and don’t scrub hard. If you have gum recession, such an abrasive toothpaste may make things worse.