America’s obsession with flawlessly white teeth has companies smiling.

While bleaching done by dentists continues to be the most effective procedure available, few can afford the high price tag that comes with it. Custom-made trays and professional gels cost upwards of $300. Zoom Laser whitening, the ultimate system that can whiten teeth in a little over an hour, runs about $1,500.

In the search for an affordable alternative, customers have turned to over-the-counter products, and companies are eagerly responding. In the last five years alone, over 130 new teeth-whitening products have hit the market.

But, with so many options, how do you know what works and what falls short of its promise? Here is a review of the options available.

How Do they Work?

Teeth whitening products work in two distinct ways. They can either remove surface stains, or they can bleach the tooth, changing its natural (intrinsic) color.

Once applied to the tooth, the bleaching agent (hydrogen peroxide, carbamide peroxide, or sodium perborate) penetrates the surface, releasing free radicals and oxidizing (bleaching) stains.