Above is a picture of me before I tried the whitening kit. (Sorry, I hate taking Selfies)
My teeth usually get SUPER sensitive when I have tried OTHER kits. I did not notice any sort of sensitivity with this product! You can also use this product with already fitted teeth trays and that is what I did. I used my clear retainer and it was super convenient!
Here is a picture of me after using 1 full pen. You cannot tell much of a different from the picture, but I assure you... There is a HUGE difference! I was so glad that I did this review! It was just in time for our new family pictures! It gave me much more confidence to take these pictures. I definitely recommend it!