Teeth whitening is normally safe when monitored; overuse or high concentrations without assistance can aggravate gums

https://spencerckgc837.raidersfanteamshop.com/the-truth-about-charcoal-toothpaste-does-it-really-whiten-1

Teeth whitening is generally safe when supervised; overuse or high concentrations without assistance can irritate gums and increase level of sensitivity-- follow instructions closely.