Osteoarthritis is the most common musculoskeletal disease in the world. While predisposing conditions have been identified, the actual cause of osteoarthritis remains unknown. Traditional treatments, most often anti-inflammatory drugs and pain relievers, produce variable results and may cause significant toxicity. The use of complementary and alternative therapies in the treatment of osteoarthritis has become more common, and particular interest has focused on glucosamine and chondroitin treatments. This study will examine the pharmacokinetics of glucosamine and chondroitin.

This study consists of two phases. In Phase I, participants will have two study visits, during which multiple blood samples will be taken to determine levels of glucosamine and chondroitin found naturally in the body. During Phase II, participants will be randomly assigned to receive glucosamine, chondroitin, or a combination of the two for 3 months. Blood samples will be taken at each of the three Phase II study visits to examine the pharmacokinetics of glucosamaine and chondroitin.