Both chemicals are integral in cartilage production at the "end" of the bone where it articulates with another bone. Your body no longer makes those two chemicals and requires an exogenous source to aid in joint healing. And it can take at least three months of ingesting those chemicals for any positive effect to take place. In other words, they need to be taken over the L O N G term and make no doubt about it. How much is it worth to you to maintain your knee joint properly?