Burned the heck out of my gums and throat. Yes, I know I was to carefully put onto just my teeth, but after it sits in your mouth, the gel thins and spreads. I've not been able to force myself to try it a third time :/

I’ve been limited in what exercise I can do because of knee pain. When I used to do leg presses there was a certain part of the bending and unbending that caused me left knee pain, and I often would lay off the press with that leg at that point, which I felt decreased the effectiveness of the leg presses and possibly might have led to an imbalance in strength between the two legs. So I quit doing them.