I have used it in tens mode on areas that cause significant pain and while I don't necessarily find any lasting effects, it helps dull the pain during use.
I'm so glad I asked if I needed any gel or other accessories and was informed a drop or two of water helps the pads get sticky again because nowhere did I see anything to inform what to do once the pads are no longer sticky enough to stay on, which in my experience happens every or nearly every usage.