I received my first kit .used it .and it did not wehitn my teeth. I was stressed at work and didn't feel like arguing with customer service so I didn't mention it for a while. Then I thought hey, you spent the money .so I sent an email explaining that the kit did not wehitn my teeth like the other commercial brands did. Soon after, I received an email with a tracking number, telling me a new kit had been sent to me, and that they stood by their product 100%. Wow. Excellent customer service. So now, I'm on my third day ..and I have to say my teeth are glow in the dark white! I must have just gotten a bad batch the first time. Stuff happens .but the key is whether the company is ready to make it right, and this company did. I've still got days and days to go but already after the third treatment, my teeth are whiter than with the other store-bought brands. Also, the type of peroxide used in this product does not cause the excrutiating pain that the other products do. Thats a plus. Excellent product and excellent customer service.