According to the book, The Arthritis Cure, there are three requirements to keep cartilage healthy: water for lubrication and nourishment proteoglycans to attract and hold the water, and collagen to keep the proteoglycans in place. Proteoglycans are large molecules made of protein and sugar. They trap water like a sponge and make cartilage resilient.1 Glucosamine sulfate figures into healthy cartilage since it is a major building block of the water-loving proteoglycans. In addition, glucosamine sulfate’s very presence stimulates the production of more proteoglycans. The fact that glucosamine sulfate increases the synthesis of these key elements of cartilage means that it actually helps repair damaged or eroded cartilage.