Rinsing With Hydrogen Peroxide: What You Need to Know

You’ve heard us mention time and time again that your smile is often the first thing people notice about you. And in the pursuit of a perfect smile, many often turn to hydrogen peroxide. But is it safe to use? We asked the experts what to know.

It must be used in the right concentration

“Using peroxide diluted appropriately can certainly help maintain gum tissue health and can slowly whiten teeth,” says New York cosmetic dentist Jason Kasarsky, DDS. “It kills bacteria and even has the power to help heal mouth sores and disinfect your toothbrush. But the key thing to remember is that you have to use it properly and dilute it to a safe percentage.”

Dr. Kasarsky says to follow the “one third, one third and one third” rule when diluting. That means that the mixture you use should include equal parts of hydrogen peroxide, water and Listerine. If you feel unsure of your mixing ability, you can use a product called Peroxyl that contains a safe amount of hydrogen peroxide. 

“There are no bad effects that can occur if you dilute it appropriately,” says Dr. Kasarsky. “If it’s not diluted properly, you can create tooth sensitivity and blanche your gums, although the negative effects typically don’t last very long. As for the rumor that rinsing with hydrogen peroxide can cause cancer, that’s a myth as it’s not a known carcinogen.”

Los Angeles cosmetic dentist Rhonda Kalasho, DDS adds that when diluted properly, hydrogen peroxide can also be effective against illness. “Most recently, hydrogen peroxide has been used as a therapeutic treatment for COVID-19,” she says. “A study from Hindawi researched the effect of a peroxide rinse and the severity of illness, and it was shown that hydrogen peroxide at a 3 percent concentration reduced hospitalization rate. In summary, peroxides are very safe to rinse with if you are just swishing and spitting and using a low concentration, i.e below 3 percent.”

“While a diluted concentration of hydrogen peroxide is marketed and sold professionally over the counter as an oral rinse, there are some concerns with its use,” says Fort Washington, PA, prosthodontist Glenn J. Wolfinger, DMD. “The major problem arises in patient’s ability to accurately dilute solutions and monitor usage to a safe level.” Dr. Kalasho adds that “Because a mouth rinse tends to go all over the mouth, a high contraction peroxide can cause a chemical burn to the oral mucosa.”

It kills the bacteria in your mouth

Conversely, Beverly Hills, CA cosmetic dentist Kourosh Maddahi, DDS says the issue with hydrogen-peroxide mixing comes down to killing off good bacteria in your oral cavity. “I am definitely against rinsing your mouth with hydrogen peroxide,” he notes. “It kills all the bacteria, which means 98 percent of the good bacteria in our mouth that help protects us against disease and infection. It can also break down enamel over time and cause tooth and root sensitivity along with gum irritation.”

It’s not an alternative to other whitening methods 

“There have been several studies that evaluated the effectiveness of using hydrogen peroxide mouthwashes to whiten teeth,” says Dr. Kalasho, who adds that most studies showed no significant difference in the color of teeth. “It has been determined that gels, either hydrogen peroxide or carbamide peroxide, do a better job at whitening the teeth and improving overall brightness.”