By Jonathan Cluett, M.D., Guide

For over two decades there has been a debate in the treatment of osteoarthritis about the use of the joint supplements glucosamine and chondroitin. Osteoarthritis is a condition that causes problems of wearing out of the normal smooth cartilage surfaces of the joints. Often called wear-and-tear arthritis, osteoarthritis causes joint pain, swelling, and deformity. Osteoarthritis is the most common type of arthritis.

How do glucosamine and chondroitin work?

Glucosamine and chondroitin are two molecules that make up the type of cartilage found within joints. Inside your joints, cartilage undergoes a constant process of breakdown and repair. However, to be properly repaired, the building blocks of cartilage must be present and available. The theory behind using the glucosamine and chondroitin joint supplements is that more of the cartilage building blocks will be available for cartilage repair.

  • Glucosamine is a precursor to a molecule called a glycosaminoglycan-this molecule is used in the formation and repair of cartilage.
  • Chondroitin is the most abundant glycosaminoglycan in cartilage and is responsible for the resiliency of cartilage.

Treatment with these joint supplements is based on the theory that oral consumption of glucosamine and chondroitin may increase the rate of formation of new cartilage by providing more of the necessary building blocks.

Do glucosamine and chondroitin supplements increase cartilage formation?

While it is an interesting theory, oral consumption of glucosamine and chondroitin has not been shown to alter the availability of these cartilage building blocks inside an arthritic joint. It has not been shown that consumption of joint supplements increases the quantity of these cartilage building blocks within any joint.

What research has investigated glucosamine and chondroitin?

There have been numerous studies to examine the treatment effects of glucosamine and chondroitin over short periods of time. Most of these studies last only one to two months; however, they have indicated that patients experienced more pain reduction when taking glucosamine and chondroitin than patients receiving a placebo. The improvement experienced by these patients was similar to improvements experienced by patients taking nonsteroidal anti-inflammatory medications (NSAIDs) that have been a mainstay of non-operative arthritis treatment. The difference is that NSAIDs carry an increased risk of side effects including gastrointestinal complaints and bleeding.

The joint supplements glucosamine and chondroitin have few side effects, and thus their use would be preferred if the effects of pain reduction were indeed the same. Furthermore, there is an indication that NSAIDs may increase the progression of arthritis, whereas glucosamine and chondroitin may offer a more protective effect to the cartilage surface.

There have been some recent investigations that are focusing on the two primary problems of earlier studies into the supplements glucosamine and chondroitin:

  • Studying more patients
  • Following these patients for a longer period of time

Because osteoarthritis is a chronic disease that progresses slowly over time, in order to test any treatment, a long period of follow-up is necessary. In one recent study, the effects of chondroitin in 372 patients over a minimum three month period was investigated. This study, which combined the data from other smaller studies, found that patients did have an improvement in their symptoms of pain.
There have also been long-term studies lasting over one year into the effects of glucosamine. These studies also have shown encouraging results. A presentation at the 1999 meeting of the American College of Rheumatology illustrated the findings of a three year long European study that compared the effects of glucosamine versus placebo in about 200 patients. The group of patients taking glucosamine had less pain and better x-ray findings than the group of patients taking the placebo.

Should I be taking glucosamine and chondroitin?

Again, the results of studies investigating glucosamine and chondroitin have been encouraging, but have not passed the test of a well-designed study to be accepted into the primary treatment plan for osteoarthritis. Furthermore, because these are unregulated supplements, a particular brand of glucosamine or chondroitin may or may not be of satisfactory quality.

Ultimately, what patients should understand, is that glucosamine and chondroitin have shown encouraging evidence that these supplements can provide help with treating osteoarthritis. However, these studies have ranged from poor to satisfactory in quality, and in order to be accepted as an effective treatment for osteoarthritis, more research must be completed.

What is known, is that there are effective treatments for osteoarthritis that every patient should be using before considering these supplements. Specifically, recommendations for weight control, exercise, proper use of medications, and joint protection are known to minimize the progression and improve symptoms of osteoarthritis. These steps must be taken by all arthritis patients for optimal treatment to take place.


  • Conn, D, et al.; Alternative Treatments and Rheumatic Disease. Bulletin on the Rheumatic Diseases. 48:1-4. 1999.
  • Muller-Fasbender, H, et al.; Glucosamine sulfate compared to ibuprofen in osteoarthritis of the knee. Osteoarthritis Cartilage. 2:61-69. 1994.
  • Leeb, B, et al.; A Metaanalysis of Chondroitin Sulfate in the Treatment of OA. Journal of Rheumatology. 27:205-211. 2000.
  • DaCamara and Dowless; Glucosamine Sulfate for Osteoarthritis. The Annals of Pharmacotherapy. 32:580-586. 1998.