I'd advise anyone using this to first take time to carefully read the manual directions for procedures and for warnings as to which areas to safely use it on and which people shouldn't use it at all. I would NOT expect it to immediately eliminate pain as an aspirin might do for a headache. To answer your questions, I used two pads on the sides of my shoulder twice a day. Sorry, but I don't recall exactly how many days I used it. Might have been a week or more. However many, it was worth it! Best wishes.