Richard G. Petty, MD

Glucosamine and Chondroitin

A study has been published in last week’s New England Journal of Medicine that seems to show that there’s no advantage in taking the popular dietary supplements glucosamine and chondroitin. Indeed that’s what has been reported in the media . But notice that I said, “Seems to show,” for on closer examination there is more to this paper than it appears.

The investigators are to be congratulated for doing the study in the first place. What they did was to take a large group of 1583 patients who all had osteoarthritis of the knees, and divide them into five groups:

  • A placebo group
  • A group that took celecoxib (Celebrex) 200mg/day
  • 1500mg of glucosamine/day
  • 1200mg of chondroitin/day
  • A combination of 1500mg of glucosamine/day and 1200mg of chondroitin/day

The study lasted 24 weeks, and the main outcome measure was pain in the knees. The study showed that although patients on Celebrex did very well compared with the placebo group, those on glucosamine and chondroitin did not do better than placebo, although the combination was better than using either supplement alone. But one of the odd things was that people with moderate to severe pain WERE helped by the combination, and in fact the combination out-performed Celebrex!

Not only does the combination seem to help people with the biggest problems with pain, but also there are some other important points:

1. The worse someone is, the bigger the room for improvement. If someone only has mild pain, you need a lot more patients to find a statistically significant improvement.

2. As in most studies, multiple measurements were done, and Celebrex was no better than placebo in 12 out of 14 of them. So if the “active comparison” failed on multiple measures, we need to be very cautious about how we interpret the study.

3. The placebo response rate in the study was 60%, while the average is 30-35%. This is a huge difference. This may be because the patients knew that they had a four in five chance of getting a treatment that might help them, so they went into the study with high expectations.

4. This is only one study, concerning one type of joint problem. There are more than 30 others that have in general been even more positive then the findings in the moderate to sever group, including a very long-term study that showed that over an eight-year period, the combination dropped the rate of knee replacement by almost 75%. It is crucially important to examine the results of any study in the context of everything else that has been known and discovered. Every type of study has to be checked, and verified.

5. The study was funded by the National Institutes of Health and is the first of two parts, with a second study of the impact of the treatments on X-rays of the knees still pending.

6. None of the groups had many side effects, but it is worth remembering that medicines of the Celebrex type are under intense scrutiny because of the possible association with cardiovascular disease.

7. Many specialists use anti-inflammatory medicines together with glucosamine/chondroitin, at least at the beginning of a course of treatment. And that makes good sense.

8. What about the dosing of the supplements? Although those are the doses used by most people, they may not always be enough. In patients who weigh more than 200 pounds, many experts recommend 2000mg of glucosamine and 1600mg of chondroitin. It is also wise to take the supplement in divided doses with food. (I have sometimes also found it very useful to add Methylsulfonylmethane (MSM), 1000mg/day to the glucosamine and chondroitin, though there is little research to support it.)

None of these treatments can be given to pregnant women or nursing mothers.

One other small caveat, if you are having surgery make sure that you tell you surgeon if you are taking these supplements. Chondroitin has minor anticoagulant activity , and so may glucosamine.

And remember that the maintenance of joint health is not just a matter of taking some supplements. It is a judicious mixture of taking the right medication when needed, together with supplements, a healthy diet containing some omega-3 fatty acids and antioxidants, exercise, management of posture, particularly of the spine, and weight management. To say nothing of ensuring that joint problems are not being compounded by psychological and relationship problems, and disturbances in the subtle systems of the body.

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About Richard G. Petty, MD
Dr. Richard G. Petty, MD is a world-renowned authority on the brain, and his revolutionary work on human energy systems has been acclaimed around the globe. He is also an accredited specialist in internal and metabolic medicine, endocrinology, psychiatry, acupuncture and homeopathy. He has been an innovator and leader of the human potential movement for over thirty years and is also an active researcher, teacher, writer, professional speaker and broadcaster. He is the author of five books, including the groundbreaking and best selling CD series Healing, Meaning and Purpose. He has taught in over 45 countries and 48 states in the last ten years, but spends as much time as possible on his horse farm in Georgia.


2 Responses to “Glucosamine and Chondroitin”
  1. Roger says:

    But one of the odd things was that people with moderate to severe pain WERE helped by the combination, and in fact the combination out-performed Celebrex!

    I am not surprised that the glucosamine/chondroitin combination helped. I know many people with RA who take it successfully, i.e. one tablet a day keeps their arthritis at bay.

    If you have RA it is always worth trying. It works for the majority of people.

  2. Richard Petty says:

    Dear Roger,

    Thank you so much for your comments.

    I hope that I made the same point about some oddities in the trial.

    There is more data to come, and the key will be to see if the supplements will prevent degradation of the joints and a reduction in the levels of circulating cytokines that can damage joints, blood vessels and the brain.

    There’s not much point in people feeling better if their cardiovascular systems are collapsing!

    Kind regards,


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