What's the latest on taking glucosamine for knee arthritis? For awhile I heard you should only take it for a few months. Then I heard you should alternate between glucosamine and chondroitin.

Enough studies have been done now on the use of chondroitin sulfate (CS) and glucosamine (GS) to show us some trends. First, it looks like these products are safe, even if they don't work for everyone.

Second, it appears that many patients do experience pain relief and improved function from taking these products. A study sponsored by the National Institutes of Health (NIH) has shed some important light on these supplements.

The study called Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT) looked at CS alone, glucosamine alone, and the two combined together. They used products that met certain standards otherwise set for drugs.

The results of the GAIT study showed that CS works better when it's combined with glucosamine. The pharmaceutical-grade supplement used most often in Europe is called Cosamin.

But all the evidence isn't overwhelming in its support of these products. Researchers say the results are at a medium level. This means further study may show different results.

Right now the opinions are split on taking CS and/or GS for arthritis. The European League Against Rheumatism strongly recommends these products. The American College of Rheumatology says the evidence is too weak to recommend their use.

The Agency for Healthcare Research and Quality specifically recommends the use of a CS/GS combination instead of an antiinflammatory drug. They make this suggestion for patients with moderate to severe arthritis pain.

It's always a good idea to check with your doctor before taking any product. This is especially true for CS/GS, which is an unregulated, over-the-counter supplement. Your health, current use of other medications, or other factors may be important factors.