Long-Term Effects of Glucosamine

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Long-Term Effects of Glucosamine

Question:

I have been taking 1000 mg of glucosamine daily for at least a couple of years. It has done wonders for my cartilage trouble and now I do not get water on the knee. Do I have to stop taking it?

Answer:

Unfortunately, there is no compelling or reliable information available to answer your question. Without long-term scientific research, it's impossible to know whether stopping or continuing the over-the-counter supplement glucosamine is the better choice.

There have been some very good studies of glucosamine in the treatment of osteoarthritis. Studies to date suggest that glucosamine use is associated with reduced pain from osteoarthritis of the knee similar in magnitude to an anti-inflammatory medication (such as ibuprofen or naproxen). For unclear reasons, glucosamine may improve symptoms for those with moderate or severe symptoms more reliably than for those with mild joint pain. There is significant controversy (and skepticism) about claims that glucosamine has other benefits, such as healing damaged joints or preventing future damage.

As for other forms of arthritis (such as rheumatoid arthritis) or for osteoarthritis affecting joints other than the knee, we have even less information about glucosamine's effectiveness. In fact, a well-designed study published in February 2008 found that glucosamine therapy was unhelpful for osteoarthritis of the hip.

It's worth noting that "water on the knee" (joint swelling) is not one of the proven benefits of glucosamine. It's possible that you would have improved even without taking the supplement.

But your question seems more about safety. Glucosamine is considered quite safe. Significant side effects are rare. These include allergic reactions (especially among people who have reactions to shellfish or iodine), stomach upset, sedation, insomnia, and sun sensitivity. There has been concern that glucosamine might cause or worsen diabetes but there's little evidence that this is true.

Since you are taking less than the standard dose of glucosamine for arthritis (500 mg taken 3 times each day), it's even less likely that the supplement will cause you any harm. That said, long-term studies of safety or effectiveness of glucosamine at this dose are not available. Finally, it's worth keeping in mind that because the FDA does not regulate non-prescription supplements such as glucosamine, its purity, strength, and actions may vary from bottle to bottle or brand to brand.

Talk to your doctor about the cause of your knee swelling and the safety of taking glucosamine over the long-term. There may be safer and more effective ways of treating your joint disease, including not taking any medication!

Last updated:	March 03, 2009