Opalescence Pf 35% Teeth Whitening 4 pk (GUARANTEED FRESH !)

This whitening gel is very strong. It does a great job. One thing people should be aware of though is that you need to be very careful how much you use. Not anywhere did I read that you cannot get the stuff on your gums, so what did I do -got too much on my gums. It started to burn, but I ignored it thinking the stuff was just working real good. No. Bad. I wasn't able to hold out very long. No permanent damage, but real tender for a couple of days. I just wish I knew it going in. Now I am more careful. No biggy, just be careful and the stuff works great. I would definitively purchase again/recommend.

My dentist gave me the 10 percent solution of this product and I wasnt' finding it was doing anything so ordered the 35 percent solution and used it one time for 30 minutes. It whitenend the hell out of my teeth, but also made my teeth really sensitive for about a week. I tried it again a couple of weeks later and left on only ten minutes and again had sensitive teeth. So...if you tend to have sensitive teeth, I'd say go with a less powerful solution. On the other hand, if you need white teeth fast, this is your product. It worked really fast and really well to remove years of tea stains to my teeth. The price was really good at Amazon, way less than purchasing through the dentist's office.

This seems to be the real deal and its doing the job with the trays I got from my dentist. I haven't had any sensitivity problems with this higher strength, perhaps because I am using a prescription high-fluoride toothpaste before and after I use it (based on my dentist recommendation).