What about joint supplements, I heard they work?

I've read many studies that show Glucosamine Chondroitin For Arthritis, Osteoarthritis, and Joint Pain works well. These studies state that Glucosamine and Chondroitin could not only relieve the symptoms of arthritis, but also reverse some of the effects of osteoarthritis, alleviating joint pain and lubricating joints. Could this be why Glucosamine and Chondroitin are the most popular natural compound in the United States for people of all ages. Does Glucosamine and Chondroitin really work?