Unfortunately, there’s no evidence to suggest that banana peels really do whiten teeth. While the minerals in bananas promote dental health, they’re unlikely to brighten your smile.
There are two main ways to whiten teeth: abrasion and bleaching. Abrasion is when a rough texture — such as toothpaste — is rubbed against your enamel. This can wear down stains that build up on the outer surface. (But be careful: When a material is too abrasive, it can damage the enamel.) Bleaching usually involves hydrogen peroxide. This is the same chemical that can bleach your hair or clothes.
Rubbing banana peels on your teeth is not abrasive enough to remove stains. Nor does the peel contain any bleaching chemicals.
But bananas are still a delicious choice for a snack. They’re naturally sweet and low in acid. What’s more, the potassium in bananas improves bone mineral density. It also works with magnesium to prevent blood from becoming too acidic, which can leach calcium from your bones and teeth.
A banana peel rub is generally harmless for your teeth. But if you opt for orange or lemon peels — also promoted online as teeth whitening hacks — you risk damaging your enamel. Citric fruits have high levels of acid, which can weaken your enamel. This puts your teeth at risk for decay and can increase temperature sensitivity.
Talk to your dentist before trying to whiten your teeth at home. Regular dental cleanings can remove plaque and tartar to keep your smile healthy and bright.