A sampling of some teeth whitening kits in the UK revealed that they may actually do more harm that good. The UK’s Trading Standards Institute (TSI) tested 16 kits and found that a whopping 14 had in excessive levels of hydrogen peroxide. One whitening kit was reported to have more than 230 times the legal limit of hydrogen peroxide. Hydrogen peroxide, the active ingredient used in most teeth whitening kits can result in burns to the mouth. According to the TSI the legal limit of hydrogen peroxide is o.1 percent.

Of the kits tested, two, Boots Expert Teeth Whitening Programme and Brilliant Tooth Whitening System met established standards. The Cosmetic Products Regulations has guidelines on the acceptable level of hydrogen peroxide in teeth whitening kits.

The TSI has recommended that the offending products be removed from the market. However, they have not named the brands as legal action is being considered.