Since 1997 use of these supplements has exploded – the ingredients come from animal sources such as crab shells and cow, pig or chicken cartilage and have been thought to relieve knee pain and perhaps repair the cells that line the joint, revitalizing worn cartilage. Overall the results of many studies have showed no significant relief in those who took the supplements, but closer analysis found that a small subgroup of people- with moderate to severe pain did get significant relief. The first large scale clinical trail on any dietary supplements Glucosamine/Chondroitin Arthritis Intervention Trail (GAIT) performed over five years with 1583 patients showed it is affective with people with moderate to severe pain. Critics of the study point out that people with mild pain would have difficulty discerning a benefit from the supplements. Those with moderate to severe pain were more likely to perceive a benefit as they had more room for improvement. Take home message: Other studies have shown positive effects. It is extremely safe – thus worth trying. Speak to you physician before taking any supplements.