Other name(s):

chitosamine, 2-amino-2deoxy-D-glucose

General description

Glucosamine is a natural substance. It may ease symptoms of osteoarthritis.

Glucosamine is found in chitin. This is the fibrous material that makes up the exoskeleton of crustaceans and insects. It’s also found in mucoproteins and mucopolysaccharides. These are made by many animals.

Medically valid uses

A long-term clinical trial found that glucosamine, when taken with chondroitin, decreased knee pain in people with moderate to severe arthritis. This study was funded by the National Center for Complementary and Alternative Medicine and the National Institute of Arthritis and Musculoskeletal and Skin Diseases. But the combination was no better than a placebo (sugar pill) in treating mild arthritis pain. Glucosamine alone was not helpful in people with mild or moderate to severe knee pain.

Smaller, earlier studies showed that using glucosamine for three years helped slow the progression of knee arthritis. It was better than a placebo and ibuprofen for pain relief. 

Unsubstantiated claims

Please note that this section reports on claims that have not yet been substantiated through studies.

Glucosamine may help prevent joint overuse symptoms. It also may reduce symptoms of temporal mandibular joint (TMJ) disease.

Dosing format

The suggested dose of glucosamine is 400–500 mg taken three times a day. Higher doses are sometimes used to ease arthritis symptoms.

Significant amounts of glucosamine aren’t in normal food sources. You’d have to take it as a supplement.

Glucosamine sulfate comes with other materials. These can include chondroitin sulfate or manganese ascorbate.

Women who are pregnant or breastfeeding should talk to their healthcare providers before taking any supplements.

Side effects, toxicity, and interactions

Glucosamine causes fewer side effects than other arthritis medicines. However, it can still cause side effects. These can include mild gastrointestinal problems, drowsiness, and skin reactions.

People with diabetes should talk to their healthcare providers before taking glucosamine. It may make insulin resistance worse. This is especially true for high doses.

If you’re taking warfarin, you shouldn’t take glucosamine. It may increase the blood thinning effects of warfarin. This can increase your risk of bruising and bleeding.

Additional information

It isn’t known exactly how glucosamine works to treat arthritis. But there are some theories.

Some studies suggest that it’s needed for the biosynthesis of glycosaminoglycans and hyaluronic acid. Large amounts of glucosamine may increase how much of these substances your body makes. These substances are needed for joint cartilage and synovium. Or glucosamine may prompt the production of hyaluronic acid.

When taken by mouth, glucosamine concentrates in the articular cartilage of the joints.