It doesn’t work. Only whitened my teeth a little the first time. Next day, went back to normal colour I started with and did not even whiten after doing it 5 days in a row. Wasted time talking to the customer service who responded with every one has different teeth! I’ve had better results from another vendor selling their whitening kits in our local mall! Hismile is a big scam!! I’ve literally thrown $187 in the rubbish. What a waste.