Activated charcoal toothpaste doesn't actually whiten teeth better than other options—in fact, some studies found it performed worse. The real concern: it's significantly more abrasive than alternatives, meaning it can wear down enamel over time.

Researchers reviewed 11 peer-reviewed studies (out of 208 initial articles) that tested activated charcoal toothpaste on both human teeth and extracted teeth in lab settings. They looked at both whitening effectiveness and safety/abrasiveness.

Funding not disclosed in abstract