I have read it works but the blood supply to cartilage is poor so the mechanism of pain relief has to be another way in the short run, in the Long run Cartilage regeneration is possible with the use of low load long duration activities. , for knees the use of a Total Gym at low levels with closed chain activities has shown to promote cartilage regeneration and growth. This is a long duration in Rx. Glucosamine more than likely promotes the expulsion of Viscous fluids of the injured / inflamed joint. Replacing thim with nutrient rich fluids. From what I have read so this promotes decreased pain and cartilage rejuvination. KC