What you need to know about glucosamine

The full story

Osteoarthritis is a painful joint disorder that affects about 27 million adults in the US. It is the most common type of arthritis. Osteoarthritis occurs when cartilage, the tissue that cushions the ends of the bones in the joints like the knee and the hip, wears away either from injury or normal wear and tear. Without the smoothness and cushion of the cartilage, the joint becomes painful, swollen, and stiff.

Glucosamine is a natural sugar found in cartilage. It can be harvested from the shells of shellfish (e.g., shrimp, lobster) or produced synthetically in a laboratory. In the US, glucosamine is sold as a dietary supplement. It is marketed and used widely to help decrease pain related to osteoarthritis and to slow the wearing down of cartilage in humans and animals. It is frequently found in combination with chondroitin. It is claimed that glucosamine and chondroitin serve as components for the building blocks of cartilage. While adults taking glucosamine are usually advised to take 500 mg three times a day, there is no standard dosage recommendation.

There are three important factors to consider before taking glucosamine: 

• Glucosamine is a dietary supplement, not a medicine. As a supplement, its effectiveness, safety, and labeling are not regulated by the Food and Drug Administration. Some glucosamine products have been found to contain less or more glucosamine than was listed on the label. In other cases, the product was found to be contaminated.

• Consistent, strong, and definitive evidence for the effectiveness of glucosamine, alone or in combination with chondroitin, is lacking. The overall thought seems to be that glucosamine might be helpful in lessening osteoarthritis pain or it might make no difference at all.

• Glucosamine has been shown to be safe and well-tolerated. Common side effects are nausea, vomiting, abdominal pain, and diarrhea. There is a risk for severe and life-threatening allergic reactions to glucosamine in people with shellfish allergy or those with asthma.

Poison centers often receives calls for guidance when a child gets into a family member’s bottle of glucosamine (or a tablet from the dog’s food bowl!) or when someone unintentionally took their glucosamine twice. In general, people fare well with these small, unintentional ingestions.

Before taking glucosamine, talk to your doctor and be sure it is safe and appropriate for you. Always tell your doctor and pharmacist about any supplements you are taking just as you would with your prescription and over-the-counter medications. As with all home and health products, keep the bottle out of reach of children and pets.

If you suspect an adverse reaction to glucosamine, are concerned about an unintentional overdose, or have a child who might have swallowed some glucosamine tablets, immediately check the webPOISONCONTROL^® online tool or call your poison center at 1-800-222-1222 for guidance. Whether online or by phone, expert guidance is always free, confidential, and available 24 hours a day.