Glucosamine is joint supplement commonly taken to reduce the symptoms of osteoarthritis (OA) and slow joint tissue degradation. It is an aminosugar that is found naturally in the body and in shellfish; supplemental glucosamine is mainly derived from shellfish.
Before getting into the deeper details of glucosamine, it is important to have a basic understanding a joint. Joints are where bones connect and provide both a functional movement aspect as well as structural component. They are bound by connective tissue, collagen being the main component.
Glucosamine is thought to work in a number of potential ways. One of the original thoughts, that is now less supported, was that glucosamine acted as a substrate in collagen synthesis. However, a more recently supported notion is that glucosamine prevents collagen degradation by inhibiting certain inflammatory pathways that affect cartilage breakdown.
As a supplement, glucosamine appears to provide only small benefit, but benefit nonetheless. Studies show minor reductions in pain, but when compared to painkillers, glucosamine is less effective. Supplementation has also shown minor reductions in the symptoms of OA, such as joint mobility, pain, and stiffness. There also appears to be minor benefits in the prevention of collagen degradation, as shown by reductions in a biomarker of collagen breakdown. Further, through many of these potential benefits it may help improve recovery in injury rehabilitation and improve range of motion.
Glucosamine is available in a number of forms. The most effective being glucosamine sulfate salts, followed by glucosamine sulfate. Glucosamine hydrochloride is also available but is not effective. Supplementation benefits appear to be dose dependent, with greater doses showing greater effect. Amounts totaling 900-1,500 mg/day, split over 2-3 doses have been shown to be effective, with doses upwards of 2,000-3,000 mg/day also showing benefit and safety. When taken, it should be done so with food. Glucosamine is commonly paired and sold with chondroitin, another compound that may have benefit in reducing joint swelling. However, taking it on its own in one of the efficacious forms and doses appears to be sufficient.
Glucosamine supplementation has been shown to be very safe, the only side effect being potential gas. Those with a shellfish allergy do need to exercise caution though, as supplemental glucosamine is derived from shellfish.
Though research is limited, glucosamine does appear to have positive benefits on preventing collagen degradation and reducing the symptoms of OA. While glucosamine cannot treat and reverse OA, it may provide relief. While the potential benefits are small, they are better than nothing, and come with minimal risk and a small price tag. It is a reasonable supplement to include for its possible benefits with minimal downside.
Groper SS, Smith JL. Advanced Nutrition and Metabolism. 6th ed. Belmont, CA: Wadsworth, Cengage Learning; 2013.