The first few nights after I got it, I put it on one knee, even though both of them were hurting. I thought I would do it this way so I could just see if there was any obvious benefit to the one knee. It sure felt a lot better the first morning as compared to the other knee. I have been putting it on both of them recently and I really think it helps a lot. I have had weak knees since high school and had one knee surgery. It really seems to help them out. Thank you so much for hooking me up with it!