Glucosamine And Chondroitin Update
Chester J. Zelasko, Ph.D. | March 31, 2006

Researchers have been at it again and the headlines reflect what they’ve found: glucosamine and chondroitin are ineffective to reduce the pain of osteoarthritis. Or are they? Let’s take a closer look.

The Study
The Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT) is a multicenter clinical trial (1) sponsored by the National Institutes of Health. That means the subjects--close to 1,600--were recruited from all areas of the country. They were split into five treatment groups:
  • Placebo
  • 1,500 mgs of glucosamine
  • 1,200 mgs of chondroitin
  • Both glucosamine and chondroitin
  • 200 mgs of celecoxib, commonly known as Celebrex
The researchers used both subject and clinician observations of joint pain, joint swelling, range of motion, lifestyle observations (could they do more or less than before treatment), and the amount of pain relievers other than non-steroidal anti-inflammatories used to control pain. The study lasted 24 weeks.

How well the treatment worked to reduce the various pain indices are summarized below:
  • Placebo--60.1% improvement
  • Glucosamine--64.0% improvement C
  • hondroitin sulfate--65.4% improvement
  • Glucosamine and chondroitin--66.6% improvement
  • Celecoxib--70.1% improvement
Only the pharmaceutical group (Celebrex) reached statistical significance. The researchers concluded that glucosamine and chondroitin, alone or combined, were ineffective in reducing pain, even though those groups reported substantial reduction in pain.

The Problem
This was a well-designed study that had one major flaw: there were no objective measurements used to measure the efficacy of the supplements. No matter how well designed, pain questionnaires are still subjective because they ask people how they feel. Pain-relief studies are always plagued with this problem. However, there are other ways of assessing the effectiveness of the supplements.

The first would be to use radiographic (x-ray) analysis of the knee joints. This type of analysis would examine changes in joint space--in other words, was the distance between the femur (thigh) and the tibia (shin) bones increased, decreased, or did it remain the same? Prior research suggests that glucosamine use prevents continued diminishment of the joint margin, resulting in a reduction in pain using some of the same pain indices used in the current study (2,3).

Another way of assessing efficacy would be to use magnetic resonance imaging (MRI). This technique can measure the thickness of the cartilage on the ends of the bone. Previous research used this technique to monitor changes in serum markers that might be indicative of further degeneration (4).

Using these types of objective measurements would have dramatically increased the cost of the clinical trial, but as it is, we’re left with more questions than answers. The biggest question is why did 60% of those not taking either supplements or pharmaceuticals experience pain relief? What does that mean in comparison to the reduction in pain reported by the other groups? And while statistically significant, a 10% difference in pain relief hardly justifies the expense of using the pharmaceutical.

What should you do?
If you’ve used either supplement and it seems to be effective, stay with it. If you haven’t taken it, try it for 3-6 months to see if it helps.

One question that hasn’t been answered in any of these trials is whether using the nutrients at a younger age might prevent osteoarthritis (the subjects’ mean age was 59). Age may be a significant factor in determining whether glucosamine or chondroitin will be effective.

  1. Clegg DO, et al. Glucosamine, Chondroitin Sulfate, and the Two in Combination for Painful Knee Osteoarthritis. N Engl J Med 2006;354:795-808.

  2. Pavelka K et al. Glucosamine sulfate use and delay of progression of knee osteoarthritis: a 3-year, randomized, placebo-controlled, double-blind study. Arch Intern Med. 2002;162(18):2113-23.

  3. Bruyere O et al. Glucosamine sulfate reduces osteoarthritis progression in postmenopausal women with knee osteoarthritis: evidence from two 3-year studies. Menopause. 2004;11(2):138-43.

  4. Bruyere O, et al. Osteoarthritis, magnetic resonance imaging and biochemical markers: a one-year prospective study. Ann Rheum Dis. 2006.
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