I really do like the whitening job these did, however I wish the process were more efficient. This comes with 14 strips for top & bottom teeth, and I have wasted at least 3 packets trying to figure out which side was the side to apply to your teeth, since it isn't specified. The taste was also very off-putting as I could taste a bit of the hydrogen peroxide used in the strips. They also tear very easily but once I apply the strips (on dry teeth) they stay on well.
The strips claim to show a dramatic difference only three days of using it and I did see a nice change within that time, however it was nothing dramatic. I've used about 8 or 9 strips, one every few days instead of every day because my did gums did hurt with everyday use. The real shocking moment was during one of the few times I used a strip- once I removed them from my top and bottom teeth, I didn't wash off the residue because it didn't tell me to. BIG mistake. The next morning, my lip was so swollen it looked like I'd gotten a lip enlarging injection!!!! It was only on my top lip, but so swollen and so sore that I couldn't even rub my lips together. The inside of my upper lip also had peeling and 'burnt' wounds that took a good few days to finally start healing. I'm positive the 'wounds' are chemical burns from the strip. Needless to say, it was an awful experience. I haven't seen anyone mention this yet but I would wash off the sticky residue left behind on your teeth-it makes sense because whitening chemicals damage the enamel if overused and surely could damage anything inside of your mouth. Now, I swish water after whitening to get the residue off and rub my teeth with a towel just in case!
Overall, pretty good whitening, packaging should definitely be improved, price was fine ($20 at Target,) and instructions should be more clear.