That said, he cautions that there aren't any long-term studies on activated charcoal as an ingredient in toothpaste.
"The science of charcoal 'attracting' particles has been well-studied in hospital toxicology departments and air filtering systems, but I would wait for more research to determine its true safety, especially when used in the mouth," says Trey Wilson, DDS, a New York City-based dentist. "For example, how does charcoal interact with medicines if swallowed? And how does it affect healthy oral bacteria?"
If your main concern is whiter teeth, Dr. Wilson says home whitening kits or an in-office dental exam will get you the noticeably brighter results you're after. Or for a more natural approach, he suggests swiping the inside of an orange peel over teeth: "It works subtly, but safely."
What to know before you try charcoal toothpaste
If you do decide to use activated charcoal toothpaste, dentists agree that you should do so cautiously and sparingly. Brush with it no more than once every other week, and not for an extended period of time, even if your teeth feel normal.
"It's an abrasive ingredient," Dr. Cassis says, and frequent use could wear down the enamel on your teeth. (That's why certain people should avoid activated charcoal toothpaste altogether: "If you have a lot of recession of gum tissue, the roots of the teeth may become sensitive as a result of the abrasive quality to charcoal toothpastes," says Dr. Wilson.)
Dr. Cassis recommends trying a charcoal toothpaste from a reputable brand and taking note of any unusual symptoms, like raw or bleeding gums and an increase in sensitivity. If you experience any of these symptoms, stop using charcoal toothpaste right away and make an appointment with your dentist.