Glucosamine is a natural substance.
It is found in a fibrous material called chitin. It makes up the outer shells of shellfish and insects.
Glucosamine and chondroitin have been studied as a therapy for hip and knee osteoarthritis in multiple trials with conflicting results. A meta-analysis of 10 trials with over 3,000 patients with hip and knee osteoarthritis did not show a benefit of the supplement on pain or progression of osteoarthritis.
It isn’t known how glucosamine works to treat arthritis. But there are some theories. When taken by mouth, it builds up in the cartilage of the joints. Some studies suggest that it’s needed to help make glycosaminoglycans and hyaluronic acid. Large amounts of glucosamine may increase how much of these your body makes. These are needed for maintaining joint cartilage and synovium.
There may be benefits that have not yet been proven through research.
Glucosamine may help prevent symptoms of joint overuse.
Large amounts of glucosamine aren’t in food sources. You have to take it as a supplement. The advised dose is 400 mg to 500 mg taken 3 times a day.
Glucosamine comes with other substances. It may come with chondroitin sulfate. Or it may come with manganese ascorbate.
Side effects of glucosamine include:
Mild gastrointestinal problems
If you have diabetes, talk to your healthcare provider before taking glucosamine. It may make insulin resistance worse. This is a greater risk with high doses.
If you’re taking a blood thinner such as warfarin, don't take glucosamine. It may increase the effects of warfarin. This may thin your blood too much. This can raise your risk of bruising and bleeding.
If you are pregnant or breastfeeding, talk with your healthcare provider before taking any supplements.