The Hope and Hype of Glucosamine and Chondroitin

About the dietary supplements

Bones and muscles of the kneeGAIT is the first large-scale study in the United States to test the effects of the dietary supplements glucosamine and chondroitin sulfate for the treatment of knee osteoarthritis. This clinical trial tested whether glucosamine and chondroitin, used separately or in combination, reduced pain in people with knee osteoarthritis.

Glucosamine and chondroitin sulfate are substances found naturally in the body. Glucosamine is believed to play a role in cartilage formation and repair, while Chondroitin Sulfate is thought to give cartilage its elasticity. Both supplements also have some anti-inflammatory effects that may account for the pain relief.

Both glucosamine and chondroitin sulfate are sold over-the-counter as dietary or nutritional supplements. They are extracted from animal tissue: glucosamine from crab, lobster or shrimp shells; and chondroitin sulfate from animal cartilage, such as tracheas or shark cartilage.

The benefit

In the GAIT study, participants who took glucosamine and chondroitin and had moderate-to-severe pain, experienced significant pain relief–about 79 percent had a 20 percent or greater reduction in pain versus about 54 percent for placebo.  However, the participants in the mild pain subset who took glucosamine and chondroitin sulfate, did not experience statistically significant pain relief.  These findings are consistent with the results physicians report in their actual office practice where some people get pain relief, and some don’t.

While it has been speculated that glucosamine supplements may be able to help the body repair damaged cartilage, this has yet to be proven, and in the GAIT study there was in fact no slowing of loss of cartilage in patients who took glucosamine and chondroitin, together or alone.  This was determined after assessing the x-ray data on  581 knees of participants in this study.  More research needs to be done, but at this point, there appears to be no benefit from taking these dietary supplements, other than for pain relief in those experiencing moderate-to-severe pain.

How to take glucosamine and chondroitin

Because dietary supplements are unregulated, the quality and content of products on the store shelves may vary widely. Identical products of glucosamine and chondroitin used in the GAIT study may not be commercially available.  A well-respected private laboratory, Consumer Lab.com performs independent tests on dietary supplements  which it publishes online.  However, these results are only available for an annual subscription fee.  The National Arthritis Foundation recommends simply choosing only products sold by large, well-established companies. 

If you decide to take these supplements:

  • Always consult your doctor before deciding to try these supplements, and make sure that osteoarthritis is the cause of your pain.
  • Consult your doctor about the proper dosage. The amount used in studies of glucosamine was 1,500 mg per day and in studies of chondroitin sulfate, 1,200 mg per day was used. Divide the daily total into three doses per day.
  • You can try the supplements along with your current medications for three months. If you don’t experience any difference in your symptoms within this time, you probably will not get any relief from using the supplements. If the supplements are having a beneficial effect, continue on the supplement, but it may be possible to reduce the dose after the first few months:
    • First two months: 1500 mg glucosamine and 1,200 mg chondroitin per day in three divided doses 
    • Next month: try reducing the dose to 1,000 mg of glucosamine and 800 mg of chondroitin, in two divided doses. 
    • Next month: try reducing to 500 mg glucosamine and 400 mg of chondroitin in one dose
    • If symptoms return,  increase to the full dosage.
  • Do not stop or reduce your current prescribed medications without talking with your doctor.
  • Choose products sold by large, well-established companies that can be held accountable.
  • Read the product labels carefully to make sure the ingredient lists make sense to you. If you have trouble, ask your pharmacists for help.
  • Recommended doses should cost about $1 to $3 per day, but most insurance companies do not cover this cost.

Side Effects

Both glucosamine and chondroitin sulfate have been used in Europe for several years, with few reported side effects and in most human studies, glucosamine sulfate has been well tolerated for 30 to 90 days. But these supplements are not appropriate for all forms of arthritis or for all people.

Pregnant women should not take this or anything else without asking their obstetrician.  Diabetics should be especially cautious–It remains unclear if glucosamine alters blood sugar levels. Since glucosamine can be made from the shells of shrimp, crab, and other shellfish, people with shellfish allergy or iodine hypersensitivity may theoretically have an allergic reaction to glucosamine products.  There are reported cases suggesting a link between glucosamine/chondroitin products and asthma exacerbations.  In theory glucosamine may increase the risk of bleeding. Caution is advised in patients with bleeding disorders or taking drugs that may increase the risk of bleeding.

Side effects may include upset stomach, drowsiness, insomnia, headache, skin reactions, sun sensitivity, and nail toughening. There are rare reports of abdominal pain, loss of appetite, vomiting, nausea, flatulence (gas), constipation, heartburn, and diarrhea.

Image of the knee courtesy of the National Institute of Musculoskeletal and Skin Diseases

via “Questions and Answers: NIH Glucosamine/chondroitin Arthritis Intervention Trial Primary Study (GAIT)”, (The University of Utah, School of Medicine coordinated this study, which was conducted at 16 rheumatology research centers across the United States.) National Center for Complementary and Alternative Medicine (NCCAM), January 09, 2009

via “Glucosamine and Chondroitin Sulfate”, Arthritis Foundation

via “Glucosamine and Chondroitin Sulfate“, American Academy of Orthopedic Surgeons

 

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2 Responses to “The Hope and Hype of Glucosamine and Chondroitin”


  1. This seems like a nutritional supplement that is ripe for the making. This is a very interesting problem and I look forward to hearing about more progress related to this issue soon.

  2. Thank you for sharing this information. There are many people who are suffering from arthritis in the US and around the world. The GAIT study has contributed a lot of information on arthritis and its medication. Taking the right nutritional supplements can alleviate the condition.

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