Working in pharmacy, I saw this stuff become super popular, but recently it has become less so. As has been stated already, it is worth a try, but only because there are a lot of anecdotal positive results. This is the case with a lot of supplements (aside from vitamins and the like). Talk to your orthopedist if you really want to figure out the cause of your knee woes, and see if he can do anything for you. One of the best things you can do is find a way to exercise the surrounding tissue/muscle specifically.