(See also Overview of Dietary Supplements.)
Chondroitin sulfate is a glycosaminoglycan, a natural component of cartilage. It is extracted from shark or cow cartilage or manufactured synthetically. Its composition can vary. It is frequently combined with glucosamine.
Chondroitin sulfate is used to treat osteoarthritis. Scientific evidence shows no benefit when chondroitin sulfate is taken by itself. However, evidence suggests that in combination with glucosamine, it may reduce joint pain, improve joint mobility, and allow reduction of the doses of conventional anti-inflammatory drugs when it is taken for 6 to 24 mo. Effects over longer periods are unclear. Mechanism is unknown. Dose is 600 mg po once/day to 400 mg po tid.
Evidence on efficacy of chondroitin sulfate is conflicting. Until recently, only small trials had studied chondroitin sulfate alone or in combination with glucosamine to treat osteoarthritis. The Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT), a large, randomized, double-blinded, placebo-controlled, multicenter clinical trial studied use of glucosamine (500 mg po tid), chondroitin sulfate (400 mg po tid), and use of both drugs to treat osteoarthritis of the knee; in the group as a whole, pain was not reduced. However, exploratory subanalyses suggested efficacy in a subgroup of patients with moderate-to-severe knee pain (1).
A meta-analysis has also suggested that the benefit of chondroitin, if any, is limited (2). It has been suggested the reason for conflicting symptomatic benefit is due to the poor quality of several food-grade chondroitin sulfate supplements and that pharmaceutical-grade chondroitin sulfate with defined percent purity and sequences of oligosaccharides is efficacious and be used for treatment (3). Heterogeneity of osteoarthritic symptoms and causes also contribute to the difficulty of use in clinical practice.
Chondroitin sulfate may increase the anticoagulant action of warfarin (4).
Clegg DO, Reda DJ, Harris CL, et al. Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis. N Engl J Med 354(8):795-808, 2006.
Reichenbach S, Sterchi R, Scherer M, et al. Meta-analysis: chondroitin for osteoarthritis of the knee or hip. Ann Intern Med 146(8):580-590, 2007.
Hochberg M, Chevalier X, Henrotin Y, et al. Symptom and structure modification in osteoarthritis with pharmaceutical-grade chondroitin sulfate: what's the evidence? Curr Med Res Opin 29(3): 259-267, 2013.
Knudsen JF, Sokol GH. Potential glucosamine-warfarin interaction resulting in increased international normalized ratio: case report and review of the literature and MedWatch database. Pharmacotherapy 28(4):540-548, 2008.