Charcoal toothpaste is one of the most heavily marketed whitening products of the last decade and one of the least supported by clinical evidence.
The 2017 JADA review
Brooks, Bashirelahi and Reynolds published a systematic literature review in the Journal of the American Dental Association concluding that dental clinicians and patients should be cautious when using charcoal and charcoal-based dentifrices, and that there is insufficient clinical and laboratory data to substantiate the cosmetic and health claims made by their manufacturers.
A 2019 British Dental Journal review by Greenwall, Greenwall-Cohen and Wilson reached a similar conclusion and additionally raised concerns about abrasivity and lack of fluoride in many charcoal formulations.
Two practical risks
Abrasivity: many charcoal pastes exceed the RDA (Relative Dentin Abrasivity) values recommended for daily use, which over time can wear enamel and expose dentin, ironically making teeth look yellower.
Missing fluoride: several popular charcoal formulations omit fluoride entirely, removing the single best-evidenced cavity-prevention ingredient in toothpaste.
What to use instead
For extrinsic surface stain, an ADA-Accepted whitening toothpaste that pairs a mild polishing agent with fluoride is a lower-risk starting point. For deeper color change, peroxide-based products with published clinical evidence remain the reference standard.