I have been using this for about a week now, twice a day for two minutes at a time like instructed.  I do not smoke, but I drink coffee and cola on a daily basis and I can't believe the results I got after only ONE use!  Not to mention, after a week's time my teeth are now shiny and white, I cant' believe how well this has worked!  I have tried the Sapphire whitening system (from the dentists office) and that doesn't even COMPARE to supersmile!  Needless to say, I won't be using the Sapphire system anymore!