Janina ultra white maxiwhite whitening strips 7 day system has been developed to provide visibly whiter teeth without the use of hydrogen peroxide the hydrogen peroxide free formula is based on an innovative and enamel friendly whitening ingredient that removes stains and safely whiten natural teeth convenient and easy to use the mint flavoured strips can be used twice a day for 7 consecutive days for fast results or once a day for results in 14 days if preferred each application only