Glucosamine is a naturally occurring substance that is a component of cartilage. Its main function is to help prevent the breakdown of the cartilage between the bones in their joints. Because the knee is a primary site for this breakdown, ensuring the body has a sufficient amount of glucosamine on a regular basis is necessary to both prevent knee injury and promote healthy knee cartilage and joints.
Many studies have been conducted to evaluate the effect of glucosamine supplement, often along with a similar component called chondroitin sulfate (also a naturally occurring substance), in reducing knee pain and improving the mobility of the knees of people who have osteoarthritis or rheumatoid arthritis. Both glucosamine and chondroitin help keep the cartilage healthy and moist, and when taken in liquid supplement form, can help relieve the pain of osteoarthritis of the knee and may even assist the body in repairing damaged cartilage*.
According to the Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT), for example, the authors noted “a statistically significant improvement in knee joint swelling.” When compared with acetaminophen, a prescription and over-the-counter drug often used by people who have arthritis, one study found that “glucosamine sulfate taken once a day may have more ability to control pain due to knee osteoarthritis than acetaminophen.” In the study, 318 patients who had knee osteoarthritis took either 1,500 glucosamine sulfate once a day, 1,000 mg acetaminophen three times a day, or placebo for six months.
Although both glucosamine and acetaminophen relieve pain, patients who took glucosamine experience more relief.
The Mayo Clinic submitted a “report card” for glucosamine, giving it an “A” for osteoarthritis of the knee and a “B” for osteoarthritis generally. Investigators have noted that “based on human research, there is good evidence to support the use of glucosamine sulfate in the treatment of mild-to-moderate knee osteoarthritis.” When taking glucosamine and chondroitin, the American Academy of Orthopedic Surgeons notes that “you may need to take the supplements for a couple of months before you see any results.” Many people feel it’s worth the wait, because there are few if any side effects associated with glucosamine and chondroitin as compared with NSAID drugs.