There are no supplements that have been proven to effectively prevent arthritis. Some studies suggest that glucosamine/chondroitin supplements taken regularly over several months may help decrease pain, but the data on this is not clear. Other supplements like NEMs (eggshell membrane) are also marketed to reduce joint pain, but the data is insufficient to recommend them. In terms of arthritis recommendations, exercise under supervision has been proven to be more effective than medications or supplements in reducing pain, increasing joint flexibility, strengthening muscles, and slowing the progression of arthritis. Weight loss is also recommended if you have extra weight, especially to alleviate knee pain.