Source Naturals Glucosamine Chondroitin Complex with MSMprovides four important building blocks for healthy joints and connective tissues: glucosamine, chondroitin, bioavailable sulfur (MSM), and vitamin C. Glucosamine, an amino sugar, is an essential structural component of glycosaminoglycans, large linear molecules that help to lubricate joints. Chondroitin sulfate lends additional structural support via its high degree of interaction of collagen fibers. Bioavailable sulfur (MSM) plays a critical role in the integrity of joints and connective tissues. Vitamin C, essential for the production of collagen, also serves as an effective free radical scavenger to protect cells. Molybdenum aids in complete metabolism of MSM, glucosamine, and chondroitin.