glucosamine

Glucosamine is a substance the body makes naturally, where it acts as one of the building blocks for the glycosaminoglycans that help make up joint cartilage. In the US it is sold as a dietary supplement, most often as glucosamine sulfate (and sometimes as glucosamine hydrochloride), used either alone or paired with chondroitin.

The evidence is mixed and far from settled. According to NCCIH, it remains uncertain whether glucosamine and chondroitin actually help with knee osteoarthritis symptoms, and studies of glucosamine for knee osteoarthritis pain have reached conflicting conclusions: a major NIH-sponsored study found little or no benefit, while several other studies suggested it may help. NCCIH also notes there is little evidence that glucosamine alone improves joint structure. For hip osteoarthritis, the cited NCCIH summary reports that glucosamine was no better than placebo for pain, joint function, or joint structure, and there is not enough evidence to know whether it helps osteoarthritis in other joints. Professional guidance leans negative: NCCIH states that the American College of Rheumatology conditionally recommends against glucosamine and chondroitin for knee or hip osteoarthritis, and that the American Academy of Orthopaedic Surgeons strongly recommends against them.

Glucosamine sulfate has commonly been reported in the research at roughly 1,500 mg per day, sometimes divided into smaller doses, though this figure is not specified in the cited NCCIH sources and is offered only as background. Because any benefit is uncertain and these supplements are not standardized or FDA-approved to treat osteoarthritis, talk with your doctor or pharmacist before starting glucosamine to decide whether it makes sense for you, particularly if you have other health conditions or take other medications.

NCCIH reports that no major safety problems have been identified in large studies of glucosamine and chondroitin for osteoarthritis. That said, glucosamine may raise blood glucose (blood sugar) levels in some people, so anyone with diabetes or blood-sugar concerns should be cautious and check with a clinician. Little is known about its safety during pregnancy or breastfeeding. Glucosamine is not a replacement for medical care, and anyone considering it for joint problems should speak with a health professional first.

Large studies have not shown serious side effects from glucosamine, and reported problems tend to be mild. One effect noted by NCCIH is that glucosamine may increase blood glucose in some people. Separately, because glucosamine is sometimes derived from shellfish, people with shellfish allergies may wish to be cautious and check the product source, though the cited NCCIH sources do not specifically address this point.

Per NCCIH, glucosamine and glucosamine-chondroitin products may interact with the anticoagulant (blood-thinning) drug warfarin (Coumadin) and have been associated with an increased risk of bleeding in people taking warfarin. Glucosamine may also raise blood glucose levels, which could matter for people managing diabetes. Tell your doctor or pharmacist about glucosamine if you take warfarin, diabetes medication, or any other prescription drugs.