I have to concur with the previous posts regarding glucosamine / MSM. I take both in a single tablet 2x a day. I have knee pain from old injuries and old age wear and tear (52 y.o.) and they make a noticeable improvement. They helped allow me to climb Mt. Washington in New Hampshire with our scout troop. This is the highest peak in the north east and no easy task.

As a side note, I have read that glucosamine and chondroitin are almost the same substance, one is just one step further along the decomposition process so taking both together is redundant.