I tried some new toothpastes on the market because I wanted a change as we all usually seek to find that ultimate #1 product. I developed sensitivity to my teeth from one brand in particular. I loved it but my teeth did not like it. I discovered the sensitivity as I was eating an ice cream cone. I never had a problem with "cold sensitivity" in the past. I truly believe I know the toothpaste but not saying for sure. You can tell when this problem arises, just track back to any new toothpaste you are trying out. I believe some of the whitening or enamel enhancing toothpastes are to blame, enamel enhancing protection ones mostly. You can decide this one for yourself. I tried the culprit toothpaste for about 4 weeks and then noticed this sensitivity. I stopped the toothpaste immediately even though I loved it. I went back to my original brand and continued to have the sensitivity. I couldn't stand that pain and inability to eat cold ice cream and drink my ice cappucinos, my favorite. I decided to buy Sensodyne to see if it would help the sensitivity. The answer is "Yes". I bought the cool gel fresh flavor. It's not very tasty as a matter of fact, it tastes like cardboard. It is bland with no taste. But who cares, if it works! I could finally eat ice cream and drink capuccinos. My tube has fluoride.Potassium nitrate is the active ingredient to relieve the sensitivity. The label states: builds increasing protection against painful sensitivity of the teeth d/t cold, heat, acids, sweets, or contact. I highly recommend Sensodyne toothpaste for sensitive teeth. Hopefully, I will be able to go back to my regular toothpaste again.