Prolab Glucosamine Chondroitin & MSM is an effective combination of ingredients to help promote and maintain healthy joints and connective tissue. MSM (Methylsulfonymethane) is a natural source of sulfur, which is essential for the healthy function and structure of joints. Chondroitin helps promote lubricating fluids for your joints. Glucosamine (Glucosamine Hydrochloride) aids in the rebuilding and repairing of cartilage in addition to being a component for the development of strong connective tissue.