Teeth whitening is generally safe when monitored; overuse or high concentrations without guidance can aggravate gums

https://blogfreely.net/dernesvhbz/the-reality-about-charcoal-tooth-paste-does-it-truly-whiten

Teeth whitening is typically safe when monitored; overuse or high concentrations without guidance can aggravate gums and increase level of sensitivity-- follow instructions carefully.