This was my first treatment and I am 49. The colors more evened out but overall not much whiter. I had terrible pain in my jaw. It felt like it was in a vise. And the tooth sensitivity was pretty bad too. I suspect I am not the only one because when I called I was told to swish Malibu Coconut Rum in my mouth, hold it then spit it out. I did that three times to no avail. When I told him it didn't help I was met with shock and told this was the first time it hadn't worked... thought sensitivity never happened.