I just, and I do mean JUST, completed my first 10 minutes of HiSmile teeth whitening. I took before and after photos as well, and I shared them on Instagram.
I see videos everywhere of people doing their first before and after, and they get 1-2 shades lighter their first time.
I do know everyone's teeth are different. My teeth are sensitive, and I was between a 3 and 4 on their color scale that comes in the kit. After doing my first time, I was not in pain, which was AWESOME for someone with sensitive teeth.
BUT, my teeth afterward not only did not move shades (they claim it'll do a shade a usage in their "6 shades in 6 days") but now my teeth also have SPLOTCHES of whiter color, and they look horrible! I'm willing to give it time, but I'm not happy yet.
I was given this kit for Christmas and hope my mom didn't waste money on this kit for me (if it doesn't work).
Bottom Line: No, I would not recommend this to a friend