This natural teeth whitener has nearly 19,000 reviews on Amazon -- and it's only $20

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There are many reasons to shy away from in-office teeth whitening procedures: the price, the pain, the time commitment to name a few. But Amazon's best-selling teeth whitener is offering a painless and very affordable option for those looking to brighten those chomps right at home. 

At under $20, the Active Wow Teeth Whitening Charcoal Powder Natural is appealing enough. And with nearly 19,000 reviews on Amazon (it's also sold at Walmart), we thought we'd take a closer look at what the users are saying. 

"This stuff works really well! I noticed whiter teeth after the first use. I've convinced friends with yellower teeth than mine to try and the results are dramatic! I use it a few times a week and think it works really well!" said one Amazon user. 

Said another, "I do also use a whitening toothpaste daily, and had been prior to using this product as well, but I was amazed at the difference in just 2 weeks! I used a total of 5 times in 2 weeks." A lot of the reviews didn't shy away with details on how messy the product is, but most seem satisfied with the results. 

Of course, it's important to consult your dentist about any health concerns -- one reviewer explained she consulted her dental surgeon father about the product.

"I asked him about this product which he confirmed many peoples concerns about enamel erosion ... but anyway from a professional, he said this whitening product is no worse for enamel than any other teeth whitening system, solution, or technique. ALL teeth whitening systems will slightly strip the teeth down." You can read the full review here

For more at-home teeth whitening tips, watch the video above. 

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