More than 3 years of drinking coffee and soda has really taken a toll on my teeth, and when I switched from coffee to tea, it got worse as apparently, the tannins in tea stain the teeth worse than coffee. My dentist recommended that I have my teeth professionally whitened, but when I heard the price, I went "hell no!" inside my head. Haha. So anyway, I found this and thought it might be a good alternative. And hell yes, it was! I started using this once every other day, and when I found I had no tooth sensitivity, I started using it everyday. Results started to become visible after 5 uses. My teeth looked brighter and less yellow/stained.