Welcome to Debunker, a weekly breakdown of misleading (and sometimes flat-out wrong!) news from the worlds of science, health, and more—for Beast Inside members only.
Activated charcoal has taken the millennial world by jet-black storm. It’s in our lattes, our detox cleanses, and our ice cream.
Now, it’s in our toothbrushes and toothpaste, with claims ranging from detoxification to odor reduction to whitening.
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“My teeth are actually whiter—it must be the charcoal bristles! I’m still so stunned by the results you guys…” Khloe Kardashian wrote in a Nov. 21 Instagram post touting her millennial-pink, black-bristled toothbrush. A separate brand of charcoal toothbrushes—which promises to “limit bacteria growth” and “provide a much gentler brushing experience”—made Gwyneth Paltrow’s notorious Goop Holiday Gift Guide.
But science doesn’t support the claims made by charcoal-laden dental products. Dentists warn there’s a serious lack of research and a serious lack of conclusive proof that brushing your teeth with charcoal does what it promises.
In fact, charcoal’s abrasive qualities could do more harm than good.
“I don’t believe this whitening stuff,” said Carolyn Primus, an associate adjunct professor at the Dental College of Georgia. In 2015, Primus worked with a group of dental students who studied activated charcoal tablets, which can be mixed with water to create a toothpaste-like product.
At the Academy of General Dentistry’s 2015 meeting, Primus’ students presented research where they brushed dental acrylic 2,000 times with the activated charcoal mixture. They found that the resulting acrylic was much darker than the two control groups, regular toothpaste and water.
If a consumer has a filling, that darkening effect could be even worse, Primus said. “When you have a filling, there’s always a margin between the natural tooth and the artificial filling material. And that filling, over time, can become more porous,” Primus explained. “It’s a source for recurrent decay, and the charcoal can get embedded in that area. And then it doesn’t really whiten the teeth—if you have restorations, it can darken the teeth.”
Primus added that “these are extremely fine particles. If you have flaws in your teeth, or cracks—and everybody over time gets cracks—it’s not going to be whitening. In fact, it can have the opposite effect.”
While these products have sprouted up in the past few years, activated charcoal is nothing new. The black powder, created by superheating carbon-heavy materials like coal, wood, or nutshells, is exceptionally good at binding to some contaminants and carrying them through the body—in some circumstances, it’s even used in hospitals as an emergency poison treatment.
But just because they work in some instances doesn’t mean they are a safe, purifying dental treatment.
Maria Lopez Howell, a practicing dentist in San Antonio and a consumer adviser for the American Dental Association, expressed another concern: Charcoal, especially in toothpaste, could wear down healthy enamel and expose the yellow dentin underneath.
Some dentists disagree. Cosmetic dentist Gregg Lituchy told Harper’s Bazaar that charcoal toothpaste could remove surface-level discoloring like wine or coffee stains.
But Howell thinks that’s actually cause for concern. “If it’s wearing a stain away, the really sad thing is it’s probably wearing enamel away too,” she told The Daily Beast. “And you do not want that.” If enamel gets abraded, Howell explained, teeth can become more sensitive and susceptible to decay.
The biggest problem dentists noted was the lack of large-scale studies.
“Overall, the jury is still out as to whether any activated charcoal products will make teeth whiter or reduce bacteria,” Yee-Seul Chun, an instructor at the Johns Hopkins Hospital Division of Oral and Maxillofacial Surgery/ Dentistry, told The Daily Beast via email.
“It's important to be cautious with these products due to the lack of thorough long-term research on their safety,” Chun added. “There are some studies that indicate these products may lead to potential increased caries [the scientific term for cavities and decay] and enamel abrasion.”
A spokesman for Boka, the brand listed in the Goop Holiday guide, agreed that activated charcoal toothpaste could wear down healthy enamel.
“We have concerns about the abrasiveness of charcoal toothpastes and powders, so we’ve avoided them (the grainy powders are particularly troublesome—really, any substance that’s abrasive and grainy is bad for enamel),” he told the Daily Beast via email, noting that the company does not sell any activated charcoal toothpaste.
But he denied that the same would be true for a toothbrush. “The process to actually infuse bristles requires the powder to be so fine,” he said, that it’s “entirely different.” He added that “Our bristles [that are] infused with very fine activated-charcoal are actually less abrasive than traditional nylon bristles,” and noted that the company’s “gentleness” claim wasn’t linked to the charcoal.
When it comes to antimicrobial properties, the science is similarly murky. The Boka spokesman provided a 2018 study in Contemporary Clinical Dentistry that showed a statistically significant reduction in bacteria when 50 participants used a charcoal toothbrush—but a 2017 study published in The Canadian Journal of Dental Hygiene (CDHA) came to the opposite conclusion after studying 90 participants.
The key to a healthy white smile is actually quite simple, according to Howell: brushing with a soft-bristled, ADA-approved toothbrush twice a day, getting regular checkups, and eating a healthy diet.
“For pennies and minutes, you can have oral health,” she said.
