Glucosamine is a sugar naturally produced by the body. It is one of the building blocks of cartilage. Cartilage covers and protects the ends of the bones, allowing bones to move smoothly against each other.
Chondroitin is also a natural substance found in the body. It is believed to help draw water and nutrients into the cartilage, keeping it spongy and healthy.
Methylsulfonylmethane (MSM) is an organic sulfur compound. sulfur is needed to form connective tissue. MSM also seems to act as an analgesic by lessening nerve impulses that transmit pain.