The present invention relates to a product comprising tooth whitening substance which comprises a high concentration of water, a peroxide, a gelling agent, and carrier materials. The tooth whitening substance will remain stable when stored as a thin layer. The present invention also relates to a method of storage of a tooth whitening substance and a method producing a stable thin layer of tooth whitening substance on a strip of material. Additionally, the present invention relates to the benefits obtained from the tooth whitening composition.