I have the headache too.

I used about 10 of the strips and then my teeth started hurting on the next couple of times. Then I got really busy and didn't use them. A couple weeks ago I used them on a Friday and Saturday and then had a headache all week-end which developed into one of the worst headaches I have ever had. I couldn't go to work on Monday. I didn't even think of the white strips at that point. But again, I didn't use them until this week-end. I used it Friday and was starting to get a headache Saturday, but, without making a connection, used the strips again that day. Have had a horrible sinus headache on the left side under the eye ever since. The roots of the upper teeth communicate with those sinus. I was trying to think what was the same about the two episodes that could have given me headaches. When I thought back on the history of the whitening and the area affected, I knew it was the strips. I came in and googled "Crest White strips headache". Sure enough, all this comes up. I used to work as a dental hygienist, so I know the anatomy of the teeth and head, and the nerve routes. I know where the pain I am feeling is coming from. I even wrote a paper in school on the effects of tooth whitening, so I know the product. I have no doubt where my pain stems from, and I won't be using this product any more.