A nutrient for connective tissue and joint integrity, glucosamine is a building block for the connective tissues and other cementing materials (mucopolysaccharides, "glycosaminoglycans" and "proteoglycans") that pack the cells together.
Glucosamine sulfate (GS) nutritionally supports healthy joints and the body's ability to generate and regenerate connective tissue. Glucosamine is a naturally occurring compound present in joint cartilage that is necessary for the synthesis of proteoglycans, the protein molecules responsible for giving cartilage its strength and resilience. Sulfate, another component of proteoglycans, works synergistically with glucosamine in cartilage metabolism. GS enhances and utilizes the intrinsic compounds in cartilage in order to nutritionally provide for healthy cartilage and proper joint functioning.
Other forms of glucosamine include glucosamine HCL and n-acetyl-d-glucosamine (NAG). Most studies were done with GS and there should be no need to use different forms unless you experience a negative reaction to the sulfated form.
Chondroitin sulfate should be equally effective, but is more expensive and recent product evaluations showed some did not contain the chondroitin claimed on the label. Some people challenge its claimed effectiveness because it is not as well absorbed as various forms of glucosamine. Typical doses of either are 500mg tid and sometimes lower doses for maintenance purposes.