Overview
Glucosamine and chondroitin are dietary supplements marketed for symptomatic osteoarthritis, particularly knee osteoarthritis. They are structural constituents or precursors related to cartilage extracellular matrix, but this does not establish a clinically important disease-modifying effect when taken orally.
Proposed actions
Glucosamine
Proposed effects include substrate provision for glycosaminoglycan synthesis and modulation of inflammatory pathways.
Chondroitin sulphate
Proposed effects include support of proteoglycan structure and possible anti-inflammatory effects.
Evidence in osteoarthritis
Clinical trials have produced inconsistent results. Some studies report small improvements in pain or function, while others show little or no clinically important benefit compared with placebo.
The apparent effect may differ between pharmaceutical-grade preparations and over-the-counter products because formulation and purity vary.
Disease modification
There is no consistent evidence that glucosamine or chondroitin reliably restores articular cartilage or prevents progression of established osteoarthritis.
Practical interpretation
- They should not replace established non-operative treatment such as exercise, weight management, appropriate analgesia and activity modification.
- If a patient chooses to try them, benefit should be judged by symptoms over a defined trial period.
- Treatment should be stopped if there is no meaningful improvement.
Adverse effects and caution
Generally well tolerated, but gastrointestinal symptoms may occur. Check for interactions, allergy and comorbidity before use.
References
- Major osteoarthritis guidelines and systematic reviews on glucosamine and chondroitin.