Twice a day works for me, while I am getting ready in morning and half hour before I go to bed. Used this product before and was happy with results even though I have sensitive teeth.

I only use white strips once or twice a month because I have heard it's bad for your teeth. But I only use one set of strips at a time and I can see results! Your teeth do become a little sensitive after, but it goes away after a day and it's never bad enough that you can't eat. I use this in addition to my baking soda & peroxide toothpaste and people always tell me how white my teeth look!

Effective product but make sure you don't leave the whitening strips on for more than 30 minutes- as it says in the directions. I lost track of time and left the strips on for more than 30 minutes (exactly 50 minutes) and when I took them off, my teeth got really sensitive to everything. So I stopped using them for a week. My recommendation is to use the strips every other day- twice each day- or to use the strips only once, 5 days a week.

My dentist and clinitians always want to know what I do to keep my teeth looking so naturally white! And it's this product and my regular use of baking soda with my toothpaste.

I saw a noticeable difference with the first set of strips. These are easy to use and you don't have to keep them on for long. You can also do sets of strips back to back if time is an issue. I have pretty white teeth already. I'm not sure how well these would work on someone with badly discolored teeth, but I got great results!

I've whitened my teeth before with trays and gel, which worked fairly well, but really irritated my gums, plus made my teeth sensitive. So I've been hesitant to use whitening products. The Crest strips whitened my teeth a couple of shades or so, but then seemed to stop whitening. They still look better than they did, but nothing dramatic. I was happy to find they didn't irritate my gums or cause any other problems. They're easy to use, and has been worth using to get my teeth a bit whiter.

The shade difference is noticeably visible after just first few appliances. In less then week all my co-workers ordered package for themselves. I did not need a better compliment. One of them complained that he ruined few stripes by trying to put them on. When he became more skilled he had no problems putting them on anymore. I have this weird smell/taste in my mouth and I am usually counting last ten minutes before I take them off. But, after every use I feel rewarded with more brightness added to my smile. It is hard to tell when some of the co-workers have strips on. They use phone and have moderate conversations. I am usually quiet for all 30 minutes and I prefer to rinse out residual gel from my teeth. Stripes cover only front teeth (especially if your teeth are big like mine :). But, over all it is FANTASTIC product.

Bottom line if used as directed it works well.

When I first decided to try whitening strips, I tried a store brand first and got ok results. I then decided to try the Crest White Strips to see if I could get better results and all I have to say is WOW, what a difference!! These really work. I saw a difference after the very first strip. A little awkward to use at first because the strips are so thin, but after you get use to applying the strip it is ok and after you remove each strip you get a pasty felling in your mouth that only lasts for about a minute or two. Never will go back to the store brand.

It was not easy to find time to do this in the morning, so I used them every night for 28 days instead of 14 days twice a day. They worked pretty well for me. I just had a dentist appointment shortly after using them, and the dentist and dental assistant both commented on the whiteness of my teeth. I'm in the military so they don't do cosmetic procedures for us, so it wasn't hard for them to notice how white my teeth were compared to the other soldiers they're used to seeing. Good product for me.