A dentist weighs in on the latest trend sweeping social media.

By Cassie Shortsleeve
December 14, 2017
Photo: Getty Images/Rocky89

There are some things that practically scream, Don't put me in your mouth. Charcoal is one of them. But ever since activated charcoal-coconut shells, wood, or peat processed to become super porous-made its way into beauty products, ice cream, and cleanses, it seems everything is fair game.

And now, the black stuff is popping up in a new form: activated charcoal toothpaste. A simple #charcoaltoothpaste search on Instagram will bring up nearly 12,000 posts from influencers and models touting countless brands (seriously, we lost count). "I tried it" stories are plastered all over the web, and even celebs are singing the toothpaste's praises.

The general thought with activated charcoal is that because it can bind to toxic substances in the body, it is a detoxifier in and of itself. (Spoiler alert: It's not.) With toothpaste, the claim is that activated charcoal binds to roughness on the enamel of the teeth, absorbing any stains or dirt-and whitening teeth as a result, explains Valerie Martins, D.M.D., a periodontist at Martins Dental Partners in Beverly, MA.

Problem is, a meta-analysis of research (scientists looked at 118 studies on the topic) published in the Journal of the American Dental Association (JADA) found no conclusive evidence that these products work as they say they do on both the whitening and cleaning fronts. Plus, there's a big risk in using these pastes regularly, notes Martins: While charcoal may very well bind to the enamel pores, think about it like abrasive sandpaper, she says. "If you use it too frequently, it can strip the enamel off of your teeth, which not only makes your teeth more sensitive, but more susceptible to tooth decay." A potential loss of enamel could also make you more likely to get a cavity. (Not the result you were hoping for from a trendy new paste.)

If you've tried it a few times, you likely have nothing to worry about-but because of the abrasiveness, you can seriously damage your teeth if you're swearing by this stuff on a day-to-day basis, she notes.

Martins notes that the JADA article also looked into whether or not the activated charcoal toothpaste studied (50 of them, to be exact) contained fluoride, a mineral in toothpaste that helps prevent tooth decay. Only one did. Furthermore, the authors questioned whether the charcoal would actually deactivate fluoride in the toothpaste, making it ineffective anyway.

Not to mention, if you've tried activated charcoal toothpaste-or seen photos of anyone who has-you can attest to the fact that it can be downright messy, turning people's mouths black and sometimes leaving gray residue on the edges of the teeth. (Temporary, but still-kind of defeats the point of a "whitening" toothpaste!)

There are other (safer, more effective, and less messy) DIY ways to whiten. Martins suggests brushing with a baking soda and hydrogen peroxide mixture once or twice a week. Combine about 2 tablespoons of hydrogen peroxide with 1 tablespoon of baking soda. The mildly abrasive nature of baking soda (emphasis on mild) can remove stains, naturally whitening the teeth, she notes. Just remember: This isn't a replacement for your go-to paste-just an add-on to your routine if you're looking for a natural whitener. (The main thing to avoid in a regular whitening toothpaste is anything that's highly abrasive, particularly if you have thin enamel or receding gums, as a rough paste could "cause more damage than good," she notes.)

As for other homeopathic options such as apple cider vinegar? "These are absolutely not research-based, but since they are relatively safe, people can use them at their own discretion," she says.

When it comes to other trendy products that claim to whiten teeth, proceed with caution, Martins says. For example, those whitening gels and mini LED lights you've seen everyone from the Kardashians to Bachelor stars posting about on Instagram? Martins points out that these products contain just 12 percent hydrogen peroxide, which she notes is "very low" (professional whitening products range from 20 to 35 percent)-so you can't expect professional-level results. Not to mention the fact that many celebs posting about them may have veneers-which these products can't help anyway since "porcelain is nonporous and cannot stain, ever."

And with some products, you may be exposing yourself to ingredients that haven't been proven to be safe in humans, or that research suggests can be "super dangerous when ingested," she says. Yikes. The takeaway? If you're unsure, check with your dentist before putting the latest miracle whitening product in your mouth-and don't believe everything you hear about through an Instagram ad. (Surprise!)

She also notes: "There are no such things as whitening toothbrushes-this is total marketing." The more you know....