Unfortunately Glucosamine Sulphate didn't work for me ....I felt no benefit at all but a daily Cod liver Oil tablet does keep these old bones (rheumatoid arthritis) moving.
I also have a back problem (degeneration of the spine) and find aqaua-fit (exercising in deep water) gives a tremendous amount of relief, without putting any pressure on my back ....... there are sessions at most swimmimg pools/leisure centres.
Also regular swimming can be of great benefit.