I know there's a lot of disagreement in previous studies, but I'm quite sure some people still take this stuff, so this might be of use to someone.
BBC News - Supplements for osteoarthritis 'do not work'
Effects of glucosamine, chondroitin, or placebo in patients with osteoarthritis of hip or knee: network meta-analysis -- Wandel et al. 341 -- bmj.com
Our findings indicate that glucosamine, chondroitin, and their combination do not result in a relevant reduction of joint pain nor affect joint space narrowing compared with placebo.
BBC News - Supplements for osteoarthritis 'do not work'
Effects of glucosamine, chondroitin, or placebo in patients with osteoarthritis of hip or knee: network meta-analysis -- Wandel et al. 341 -- bmj.com