Glucosamine Sulfate is a stable; clinically studied form of glucosamine; which is essential for the proper formation of tendons; ligaments; synovial fluid; bones; skin; nails; and blood vessels.* MSM is a sulfur donor; sulfur is essential for the formation of chondroitin sulfates.* Vitamin C and manganese are required for synthesis of collagen and cartilage.* Adequate vitamin D3 supports joint health.*For best results; use with Jarrow FORMULAS JarroSil ; the biologically Activated Silicon . Jarrow FORMULAS Joint Builder is Joint Sustain nutrition; providing a SODIUM FREE form of GS stabilized with only potassium chloride (KCI).Keep out of the reach of children.