No, sensitive toothpaste is not bad for your teeth. The active ingredients in this kind of toothpaste are relatively safe for use. Potassium nitrate, a common and essential ingredient in the best toothpaste for sensitive teeth, is considered the safest. Stannous fluoride, an effective desensitizer, is also considered safe without any health hazards. Generally, there's relatively low risk with the use of sensitive toothpaste. However, if you are not comfortable with the possible risk, you may seek alternative remedies.