What is glucosamine?

Glucosamine (glue-CO-suh-mean) is a natural substance that is found in cartilage, which is the padding between the bones of a joint (for example, your hip or knee). When the cartilage in your joints starts to wear away, the bones begin to rub against each other. This is called osteoarthritis (AH-stee-oh-arth-RIE-tiss). Glucosamine is also a supplement that may help to reduce osteoarthritis pain and stiffness, and improve movement, especially in the knee. You can find it in most drug or health food stores.

Is it safe?

The U.S. government does not strictly regulate supplements. Although using glucosamine to treat osteoarthritis has been tested, there is no guarantee that it works or that it is safe. Different brands may be made with different ingredients. You should always read the label. It is not known if it is safe to take glucosamine if you are pregnant.

Are there side effects?

Side effects from glucosamine are usually minor (for example, stomach pain, heartburn, or diarrhea). Glucosamine is made from the shells of shellfish. Even though people who are allergic to shellfish react to the meat, not the shell, people with these allergies should still be careful when taking glucosamine. If you have asthma, it could make your symptoms worse. Talk to your doctor if you have any side effects.

Can everyone take it?

Talk to your doctor before taking glucosamine, especially if you are sick or if you are taking other medicine (including herbs or vitamins). You should tell your doctor if you drink alcohol or caffeine, smoke, or use illegal drugs. These can affect the way glucosamine works.

How should I use it?

Glucosamine can be taken by mouth. The dose is usually 500 mg three times a day. If you don't have side effects, you should take the supplement for at least 60 days (two months) before deciding that it is not for you.

Where can I find more information?

National Center for Complementary and Alternative Medicine (Web site: http://nccam.nih.gov/research/results/gait/qa.htm)

National Arthritis Foundation (Web site: http://www.arthritis.org/conditions/alttherapies/glucosamine.asp)