Review on Greephil Whitening Effective Sensitivity Beautiful by Heather Green

I'm new to whitening products so this is my first experience with them. The first time I used it I saw a difference in my teeth, maybe 1-2 shades. However as this is my first time using whitening products I didn't know how long I had to keep my mouth open to rinse my mouth, I want to brush my teeth so it was a learning curve. However, I have had mouth guards from previous aligners so I use them to keep my mouth open. It can be a little messy but I think it's definitely worth it and most importantly there is no tooth sensitivity! Flavor is good, very weak, but in a good way.