If you suffer from joint discomfort, DONA Crystalline Glucosamine Sulfate can help. DONA is the original Crystalline Glucosamine Sulfate that has been proven effective in major clinical trials. Improving joint flexibility and overall joint health, DONA works by helping to maintain and stabilize the cartilage between the joints. Healthy cartilage keeps your joints flexible, allowing you to return to the activities you love, such as walking, climbing stairs, swimming, running, and even the simple joy of picking up your grandchild!