Does Charcoal Toothpaste Really Work?

Whitening your teeth with activated charcoal has become really popular lately. There are lots of products on Amazon from charcoal infused toothpaste to jars of pure charcoal powder (complete with a toothbrush) to brush onto your teeth. Even the big toothpaste brands like Colgate and Crest now have charcoal toothpaste versions for sale. But does it really work?

Judging by mostly 4+ star reviews of thousands of people on Amazon, it’s either a mass deception or it must be whitening something. I’ve personally talked to people (including dentists) who have used charcoal toothpaste and swear their teeth are getting whiter after just a few weeks of using it. People who use charcoal for whitening want a more natural solution for whiter teeth and want to avoid the alternative: bleaching chemicals that dehydrate the teeth and cause tooth sensitivity. On the other hand, the US Food and Drug Administration (FDA) has labelled activated charcoal as totally safe and harmless and it's approved to treat poison and drug overdoses by internally ingesting it. 

Is Charcoal Abrasive?

So charcoal might work but the concern is that charcoal toothpaste is abrasive and can actually damage the enamel on your teeth. A 2017 study showed that charcoal toothpaste will wear out the enamel in teeth. In the study, a mechanical toothbrush brushed a dental specimen for 14 minutes (equivalent to 3 months of brushing) with a popular charcoal toothpaste brand and sure enough, enamel wore off more than brushing with a plain toothbrush with just distilled water or compared to a very mild toothpaste (Strongs™ brand).

Is Charcoal Toothpaste Being Unfairly Criticized?

But is the charcoal toothpaste really more abrasive than other toothpastes? Toothpaste manufacturers rate the abrasiveness of their products in order to get FDA approval and use a measure known as an RDA (relative dentin abrasivity) rating. The higher the value, the more abrasive it is. An RDA of 100 or above is considered “highly abrasive.” Anything over 150 is considered “harmful” to your teeth. When you look at the RDA values of charcoal toothpaste, it doesn't line up with the idea that charcoal toothpaste is more abrasive than regular toothpaste. In other words, charcoal toothpaste may be abrasive, but is it any more abrasive than common non-charcoal brands that dentists recommend all the time?

Let’s look at the RDA values. Charcoal toothpastes typically have an RDA value between 70-90—in the safe range. How does this compare to other popular brands of non-charcoal toothpaste? Plain toothpaste like Colgate Regular is 68 along with brands like Close Up at 80 and Crest Regular at 110, which is pretty high for a plain toothpaste. But when you get into fancy toothpastes that promise whitening or tartar control, abrasiveness goes up dramatically. Here’s a sampling of some RDA scores of common toothpaste brands you’ll find at the local store: Sensodyne Extra Whitening - 104, Colgate Whitening - 124, Crest Extra Whitening - 130, and Colgate Tartar Control - 165. Crest White Vivid, an over-the-counter toothpaste that boasts excellent whitening ability comes in at a whopping 200! So why are chemical whitening toothpastes given a pass (ie. no blogs or studies criticizing them) when their RDA’s are all in the “harmful” range? It would have been interesting to see the 2017 study compare the charcoal toothpaste to Crest White Vivid or some other "harmfully" abrasive whitening toothpaste instead of a very mild brand.

As an adult who brushed regularly my whole life, I’ve been told by my dentist that my enamel has worn down a lot—not because I used charcoal toothpaste, but because I brushed too hard for most of my life combined with the fact that I used a medium bristle brush for most of those years—something I’ve since learned is not good. Since I had bad brushing habits (and a stiff brush), it probably wouldn’t have mattered whether I used charcoal toothpaste or the regular Colgate I’ve used my whole life.

The Charcoal Whitening Secret

But the good news about whitening with charcoal is that you can get the whitening effects of charcoal without any abrasive brushing! Sure, the brushing action together with charcoal on your teeth will also remove stains but you’re at risk of removing enamel as well. The amazing fact that no one seems to know is that charcoal toothpaste will remove the yellow from your teeth without brushing because the whitening really works through the power of adsorption. Let me explain.

How Charcoal Works

As counter-intuitive as it is to think that something black could whiten your teeth, there is a science behind activated charcoal that explains how it could whiten teeth.

Most people know that activated charcoal is used in water and air filtration, but a lot of people don’t know that it’s also used to remove color from sugar cane to make white sugar. Sugar (from sugar cane) is normally a brown color but since the 18^th century (when the process was first discovered), pure white sugar is made by filtering liquified sugar cane through activated charcoal during processing which then produces pure white sugar. No scrubbing required.

You can do a simple experiment at home to see the amazing color removing power of charcoal by literally removing the purple color from pure grape juice. Simply mix 2 tablespoons of activated charcoal powder in an 8 oz glass of Welch's grape juice, wait 5 minutes, and then pour the charcoal grape juice mix through 2 or 3 stacked coffee filters (to catch the charcoal). You’ll end up with clear-as-water liquid that tastes like grape juice. The purple color is chemically bonded to the activated charcoal and remains with the charcoal in the coffee filter. You can whiten purple grape juice using activated charcoal in a matter of minutes.

Activated charcoal is able to do this through the power of adsorption (with a “d”). This is not to be confused with absorption (with a “b”), which is when water is drawn into a sponge, for example. A(d)sorption happens when, at a microscopic level, a particle attaches itself to the pores of an activated charcoal particle using an electrical charge known as a Van der Waal force. It bonds physically at a molecular level which is why toxins in a water filter don’t leak back into the water as you push water through it over and over again.

So if activated charcoal can remove the brown from sugar, and the purple from grape juice (in literally minutes), it should be able to remove the yellow stains from your teeth (although depending on the type of stain, it could take many applications).

Use Charcoal To Whiten Teeth The Right Way

But this is what everyone’s been doing wrong: You don’t need to scrub the stains off. Meaning, you can simply let the charcoal cover your teeth for a few minutes and the stains will begin to adsorb onto the charcoal particles. It won’t happen after one application---more like a month of doing this daily. But you will see whiter teeth. Remember, it’s simply the charcoal coming in contact with the stains on your teeth that whitens. Not abrasive scrubbing.

So the best product to whiten teeth is not the charcoal infused toothpaste but the straight powder you put on your teeth with a toothbrush. Just don't brush once applied and leave for a few minutes every night. As a bonus, swishing the charcoal in your mouth when rinsing will also detoxify and remove harmful bacteria from your mouth. In fact, for thousands of years, it was a natural remedy for halitosis (bad breath). 

Charcoal toothpaste may not be for you. Bleaching kits or whitening at the dentist office works faster and arguably works better so most people prefer to go that route. But if you want to try charcoal toothpaste, don’t believe the blogs that say that charcoal is harmful. It’s not. By using all-natural charcoal without scrubbing, you can get whiter teeth naturally, instead of from bleaching chemicals found in whitening toothpaste and kits. Give it a try. You might become one of the thousands of people posting a 5 star review on Amazon.