Teeth whitening: what the research actually shows
Strips, trays, LED kits, pastes, and in-office treatments, every whitening guide we publish, organized by what you're deciding.
Whitening is chemistry, not photography. Every product that genuinely lightens teeth does it the same way: a peroxide compound oxidizes the stain molecules inside your enamel, and the size of the result depends almost entirely on two variables, the peroxide concentration and the total time it stays in contact with your teeth. That single fact explains most of what's confusing about this category. It's why a $30 strip kit can outperform a $120 LED kit, why "one-week wonder" products either underdeliver or overdo the peroxide, and why the marketing so rarely mentions concentration at all.
It also explains the category's honest limits. Peroxide works on stains, coffee, tea, wine, tobacco, and on the gradual yellowing of age. It does not change the color of crowns, veneers, or fillings, and it does little for grey discoloration from tetracycline or trauma. If a product promises otherwise, that's your first signal to close the tab.
The guides below follow that logic. We start from the evidence on what moves shade scales, weight independent trials over manufacturer studies, and treat sensitivity, the category's real cost, as seriously as results.
Start here
All whitening guides
Every published guide, most recent first.