Osteoporosis is a type of disease that occurs when bone density decreases or bone quality decreases leading to increased bone fragility and susceptibility to fracture, while osteoarthritis is a type of disease that occurs when joint pain, deformity, and dysfunction are caused by inflammation or degeneration of the synovium, cartilage, and subchondral bone in joints, especially in the lower extremities. Both diseases are common in the elderly and can easily be combined in one person. The two diseases are related to each other but are also distinctly different. Glucosamine or chondroitin sulfate is a class of polysaccharides linked by glycosidic bonds and is synthesized in the body by chondrocytes, etc. It is the main component of cartilage. In vitro, glucosamine and chondroitin sulfate have a stimulating effect on the growth of cells isolated from synovial membranes, promote the synthesis of type II collagen, reduce the synthesis of inflammatory mediators, and bring the synthesis of extracellular matrix into balance. However, because the causes of osteoarthritis are diverse, such as it may be related to obesity, mechanical wear and tear of cartilage, or due to certain inflammatory factors, the effectiveness of these two drugs for osteoarthritis is inconsistent. For mild osteoarthritis, these two drugs do not improve symptoms, but for moderate to severe osteoarthritis, about less than half of people will get symptomatic relief. Although some clinical studies have shown that both drugs can relieve the pain and improve the function of osteoarthritis, there is insufficient evidence that either drug can improve joint structure and repair cartilage. However, neither drug can improve bone density or increase bone strength, so neither drug can treat osteoporosis.