A review found that charcoal toothpastes have no evidence to back their claims up and might even do more harm than good.
Purchasing a toothpaste can be a surprisingly daunting task: how do you choose between so many similar products? Most people choose out of habit or based on recommendations from friends or dentists. As you'd expect, in addition to the well-established approaches, some fringe options have also crept on the shelves.
"Charcoal toothpastes and powders are fashionable oral hygiene products, intended for toothbrushing, extrinsic stain removal and, it is claimed, 'tooth whitening'. The popularity of charcoal toothpastes is believed to be increasing in many countries across the world," researchers start off their study.
Charcoal has become a popular novelty on the toothpaste aisle, with many people seeing it as a cheap and 'natural' alternative. However, there are a bunch of problems regarding these products. For starters, they don't contain any fluoride to help protect the teeth and facilitate remineralization. There's also no reason to believe that charcoal pastes work better than conventional products. They're essentially a very fine powder scrub, which has an abrasive effect on teeth but you can easily go overboard and wear away the protective enamel. The fine charcoal particles can also get stuck on teeth or gums, and even around fillings or cavities, causing long-term damage through abrasion. Of course, the black toothpaste can also leave behind an unpleasant grimy black look if not thoroughly washed off.
Simply put, researchers couldn't find any evidence that charcoal toothpastes are good, but they found plenty of evidence that they might be harmful unless used very carefully. Professor Damien Walmsley, from the British Dental Association, told the BBC:
"Charcoal-based toothpastes offer no silver bullets for anyone seeking a perfect smile, and come with real risks attached."
"So don't believe the hype. Anyone concerned about staining or discoloured teeth that can't be shifted by a change in diet, or improvements to their oral hygiene, should see their dentist."
Historically, charcoal has been used in several types of health applications. Ingesting some types of charcoal has been (and still is) used to relieve gas and some digestive issues. In emergency situations, activated charcoal (a very fine charcoal powder) can also be used to save people who have ingested some poisons or toxic substances, by absorbing the substance and preventing it from reaching the blood supply. In Ancient Greece and some Medieval cultures, charcoal powder is used as a rudimentary toothpaste, but modern toothpastes work so well that there's just no reason to substitute them with something less efficient.
This isn't the first study to shower doubt on charcoal toothpastes. Just two years ago, a 2017 Journal of the American Dental Association study, analyzed 100 articles on charcoal and charcoal-based toothpastes and powders, finding “insufficient clinical and laboratory data” to support their safety or effectiveness.
The study was published in the British Dental Journal.