Originally Posted by
Draconius
A friend of mine did a study on these. They eat away at the enamel on your teeth and clean the calcium layer. So your enamel layer is thinned and causes more sensitive teeth. Enjoy!
Not to dismiss your post but according to the link RicoD provided they don't harm your enamel. Maybe the report's author is in the pocket of the teeth whitening mafia.
As far as toothpastes containing acid, I think they pretty much all do, at least citric. All I know is that my stuff costs $1, contains acid, and says it's safe for everyday use(as they all do). Here's hoping they're telling the truth.