There are a lot of whitening products out there, so it might be difficult to know what's best for you. The best whitening system you can get, would be one that's as close to a professional treatment as possible. That's why I like Smile Brilliant. They offer custom fitted trays, high intensity bleaching gel, and LED lights all at a very reasonable price.
I received one of Smile Brilliant's Brilliantly Simple Packages. It contained a High intensity Ultra-Blue LED activating light, protective trays, 4ml Professional whitening gel pen, a little brush, box to put it all in, and instructions. This package is a really great deal, usually a kit like this with an LED light would cost around $100 or more, but at Smile Brilliant it is very affordable, at only $39.95.
I made sure to read through the instructions before using this kit. First, I applied the bleaching gel to all of the teeth that I wanted to whiten. Then I put the top and bottom protective trays over my teeth. Next, I put the LED light inside of my mouth and waited 20 minutes.
Having the trays and the LED light in my mouth, was pretty uncomfortable. Although a lot of whitening systems that don't come with protective trays, would just expect you to keep your mouth open for a full 20 minutes (Not going to happen!). Either that, or you close your mouth, and all of the bleach rubs off, defeating the purpose of even trying to bleach your teeth. I would recommend ordering one of their custom fitted trays, but if you don't have $80 to shell out, then it's best to just deal with the not so comfortable standard bulky trays.
After using the LED light for 20 minutes, you can leave the whitening gel on for an additional 10-60 minutes without a light. I only left mine on for an extra 10 minutes, because I knew my teeth were already pretty white to begin with.
Once, I was done my smile was much whiter and prettier. The bleaching gel, even got to the tiny spaces in between my teeth that seem to get the most discolored. Overall, I was very impressed with this kit. The gel used in conjunction with the LED light worked very well in lightening my teeth to a noticeable whiter shade. The instructions were very easy to follow and finally for the price you really can't beat it.