Glucosamine and Chondroitin: Do They Really Work?

Glucosamine and chondroitin are widely used for osteoarthritis pain. My daughter even gives them to her elderly horse. Their popularity is puzzling, since the evidence from scientific studies indicates that they don’t work. Wikipedia has a useful survey of the history, studies, criticisms, and systematic reviews (https://en.wikipedia.org/wiki/Clinical_trials_on_glucosamine_and_chondroitin). It includes a long list of references. I