“Teeth whitening pens basically work by applying a layer of bleaching gel directly onto the enamel of the teeth,” says Lipari. “This gel typically consists of carbamide peroxide or hydrogen peroxide…The higher the peroxide concentration, the more significant whitening effect the pen can have.” And as Veytsman mentions, these pens are pretty simple to use: “You just paint it on your teeth and it fizzles the stains off, preventing them from settling into the enamel,” she says.
However, the ingredient is super strong (hydrogen peroxide has the power to bleach fabrics, after all!), and many people claim it can make your teeth sensitive. Plus, preliminary research has found that hydrogen peroxide can penetrate the enamel and potentially degrade the proteins in this layer; it also has the ability to disrupt your oral microbiome, as it’s incredibly antibacterial.
That being said, hydrogen peroxide is one of the only ingredients clinically shown to brighten teeth, so it’s pretty difficult to find a peroxide-free formula, even in the clean and natural space. “So if you have sensitive teeth, it may be advisable to start with a product that has a lower peroxide concentration,” advises Lipari. “You also want to avoid getting the gel on the gum tissue to avoid irritating the tissue.”
Whitening pens are great to use in a pinch, since they’re so easy to grab and use on the go. “Teeth whitening pens can be used after you eat or drink a teeth-staining food or drink, such as coffee, tea, or red wine,” says Veytsman. “If you just had coffee, I would recommend rinsing your mouth to get all of the staining liquid out and follow it up by using a teeth whitening pen.”
If you want to use them for long-term whitening, however, consistency is key—you can’t expect a bright, movie-star smile with a single treatment. “I recommend being consistent with the whitening pen for seven to 10 days while avoiding strongly pigmented foods and drinks for that seven to 10 day period,” Lipari suggests. Various pens have slightly different instructions, so do be sure to follow the directions from your chosen product; generally, though, you may start to see some results after 10 days.