My Teeth went white within a few days

I noticed mild staining on my teeth and thought im going to have to book an appointment with the hygienist for a clean. Then one day i was off shopping and came across beverly hills formula it was going for a pound and it looked exciting so i bought it. And ive been using it for a week now. My staining has gone my teeth are bright white and my tooth enamel doesn't even look bad.Im hoping it will be amazing after another week of brushing im sure it will. Will be telling people about this.