I took glucosamine and MSM for my knees when I was marathon training. Dropped the chondroitin.

Glucosamine comes as a sulfate and a hydrochloride (HCI). So beware of shellfish allergies AND issues with sulfates.

The combo of glucosamine and MSM worked great for me back then. If I run into problems while cycling I'd do it again.

Oh, one other thing... not sure if anyone here experienced this but me and a few others I know got a bit, er... "tooty" on the MSM. It went away after about a week on the combo.