There are three proven ways to whiten teeth naturally - but here's why dentists warn against them

The number of different ways you can supposedly whiten teeth naturally has skyrocketed in recent years as teeth whitening procedures have become the number one cosmetic procedure for those looking to invest in a whiter smile. 

Unfortunately, there's really no way to whiten teeth naturally using everyday methods and products you'll likely find in your kitchen. Some, like baking soda, fruit enzymes, and activated charcoal, may work for some people but every dentist we spoke to also warned against such whitening methods for one reason. 

Whether you're looking for the best whitening toothpaste that works, or you're looking for a way to prevent yellow teeth, this is what several dentists and the science says about whitening your teeth naturally at home. Plus, the dentist-approved tips for keeping your teeth healthy. 

What makes teeth yellow? 

There are two types of teeth staining, extrinsic and intrinsic staining, explains dentist Dr Martina Hodgson, a registered dentist specializing in teeth whitening. "Extrinsic staining builds up on the surface of the teeth," she says, and it's caused by pigmentation on the enamel of your teeth from foods and drinks like red wine, tea, and coffee, along with some everyday dental products. "Some mouthwashes containing chlorhexidine, such as Corsodyl, can also stain the teeth when used for more than a couple of weeks. It's harmless though and easy for your dentist or hygienist to remove."

Intrinsic staining is a little more complex as it impacts the dentin, and the layer underneath the enamel, and there aren't any natural remedies for this kind of staining. "This is inside your teeth, caused by substances such as antibiotics like tetracycline. This is much harder to treat and will require a course of professional teeth whitening prescribed by your dentist," she says. 

How to whiten teeth naturally - the proven ways

1. Baking soda

Several studies confirm that baking soda is a safe and effective way to whiten teeth naturally. While many of them, including ones by Purdue University and Indiana University, have looked into the efficacy of baking soda-based toothpaste and found them to be highly effective in removing surface staining from teeth, another study by Tokyo Dental College specifically looked into traditional baking soda for teeth whitening. 

They studied the effects of regular baking soda and brushing with an electric toothbrush in comparison to regular fluoride toothpaste and found the former to be significantly more effective, with no more change in the roughness of the teeth than what we see with some of the best toothpaste. 

However, although it was proven that baking soda was effective at whitening teeth, the study was conducted on bovine teeth outside of the body - meaning that the natural staining potential of coffee, red wine, curry, tea, and other products wasn't an issue. If you don't eat and drink these types of products then this method may work more successfully for you. 

2. Fruit enzymes

We all know that too much sugar - even fruit sugar - is damaging for your teeth, but a 2020 study from the Pelotas Dental School and the University of Michigan found that a property in certain types of fruit can help them appear whiter in the short term. 

The study looked at papain, ficin, and bromelain, which are all types of fruit enzymes, and found that two out of three are effective in removing some surface stains. Bromelain, which is an enzyme found in pineapple, and ficin, which is found in the latex sap of the fig tree, were the two that came out on top as researchers found the enzymes showed "promising results" and they even resulted in less enamel damage than carbamide peroxide, which is used in some legal over-the-counter whitening treatments. 

Much like the leading study on baking soda for teeth whitening, the study was conducted on bovine teeth so there are some limitations to how much we can use these results for real-world application.

Earlier studies, including one by SRM Kattankulathur Dental College and Hospital, have also looked at whether fruit extracts could be a natural way to whiten teeth and found that pineapple in conjunction with hydrogen peroxide was a more effective whitener than peroxide on its own.

3. Activated charcoal

Activated charcoal is everywhere at the moment, in everything from smoothies to face washes, with some evidence from Sultan Qaboos University to suggest that it has beneficial for eliminating toxins from the body. It's a popular component of whitening toothpaste for similar reasons, but there are mixed results. 

Several studies have looked into whether activated charcoal is an effective way to whiten teeth naturally, with positive results. A study by Shahid Beheshti University of Medical Sciences, for example, looked at three different charcoal-based toothpaste and found that all three had a strong whitening effect on coffee-stained teeth as charcoal is a mild abrasive. Aristotle University of Thessaloniki looked at the effect of charcoal on human teeth specifically and found that it was successful in improving the overall color of the teeth for the same reason, but they warned that this may also come with damage to the tooth enamel. 

While other studies, like the research from Hacettepe University, have proven otherwise and suggested that charcoal-based pastes have the same whitening effect as other regular non-whitening specific toothpaste. 

Why you should never try and whiten teeth naturally

These methods have been proven to work with several studies backing up their success as natural teeth whiteners. However, a team of dental experts have warned against their use - and using other natural whitening treatments like lemon juice, oil pulling, apple cider vinegar, and turmeric.

"The only way to effectively and safely whiten teeth is to use a specific level of peroxide that can only legally be prescribed by your dentist," says Dr Hodgson, who is also the founder of The Dental Architect. "There is no evidence that things like oil pulling are effective and lemon juice is highly acidic and damaging to the enamel so should never be considered."

Baking soda, fruit enzymes, and charcoal may make your teeth look whiter initially as they are abrasives, meaning they literally scrub at the surface of your teeth when you brush your teeth properly. However, several more studies and all the dentists we spoke to also confirm that these substances may break down the enamel on your teeth - aka. the part that makes your teeth naturally look white. 

"Enamel is the hard outer coating of your teeth that protects the dentine," explains Dr Krystyna Wilcynzski, a leading cosmetic dentist. "Dentine is what the bulk of your tooth is made up of and is naturally yellow in color. Enamel is naturally white, so if you use a toothpaste that is abrasive and wears the enamel away, it becomes more translucent, causing the yellow dental to show through and eventually making your teeth appear more yellow."

It's also worth avoiding at-home teeth whitening treatments for the same reason, even if you're living in the US where many kits and treatments contain higher levels of peroxide. "Products designed to use at home will not have the level required and therefore at best are ineffective, and at worst contain ingredients that can abrade or strip the enamel off your teeth. In the long term this can cause damage to your enamel and even lead to your teeth looking more yellow," Dr Hodgson says. 

Dentist tips for whiter teeth

So ways to whiten teeth naturally should be off the list, but there are dentist-approved ways to prevent any further staining of your teeth and improve their color in the long run. This is what Faizan Zaheer, a dentist at Bupa Dental Care, and the experts have to say about maintaining a whiter smile: 

• Avoid dark foods and drink: "The natural yellowing of teeth occurs with age, but also due to the intake of dark foods and drinks such as berries, tea, coffee, red wine, curry, etc," says Zaheer. "Rather than cut out certain things, try rinsing your mouth with water and brushing your teeth after 30 minutes of having a curry, for example, to reduce stains." 
• Quit smoking: If you're a smoker (even casually) and you're worried about teeth staining, now's the time to quit. "Quitting smoking will help keep your smile bright and improve your overall general health," he says.
• Use an electric toothbrush: One of the best electric toothbrushes won't whiten your teeth but they may help prevent staining, says Dr Hodgson. "Electric toothbrushes can be superior to manual ones in preventing stain build-up," she says. 
• Use whitening toothpaste: While dentists debate the effectiveness of these, Dr Wilcynzski says they're good for maintaining your teeth's natural color. "Whitening toothpaste can also be used to maintain the color of your teeth," she says. "They work in the way that they remove extrinsic staining caused by things such as coffee and smoking."
• Make a regular hygienist appointment: "For surface discoloration, sometimes all that is needed is professional teeth cleaning by a GDC registered dentist or hygienist, which will reinvigorate the teeth and brighten the smile."
• Maintain good oral health: "Brush twice daily for two to three minutes using fluoride toothpaste and a soft toothbrush. This removes the plaque on the surface of your teeth and it's also important to floss or use interdental brushes to remove the plaque between the teeth," Zaheer says. "Using a fluoride mouthwash at a different time to brushing will also contribute to strengthening the teeth and preventing tooth decay."