Chondroitin sulfate · supplement
Evidence tier: weak
A cartilage building block that complements glucosamine. Together they slow osteoarthritis progression.
Chondroitin sulfate is a glycosaminoglycan, a long sugar chain that is a natural structural component of cartilage, where it holds water and gives the tissue its compressive springiness. The theory is that supplying it orally replenishes the building blocks and slows cartilage breakdown. The weak point is absorption: chondroitin is a very large, highly charged molecule, and whether meaningful amounts of intact chondroitin ever reach a joint after being eaten is not established. GAIT tested the structural claim directly and found no effect on joint space width, which is the evidence that matters more than the mechanism.
Weak. Chondroitin has been tested more than almost any other supplement and the more independent the trial, the smaller the effect. The definitive publicly funded trial is GAIT, the NIH Glucosamine/Chondroitin Arthritis Intervention Trial (Clegg DO et al, New England Journal of Medicine 2006, N=1,583): chondroitin alone, glucosamine alone, and the combination all FAILED the primary endpoint against placebo for knee osteoarthritis pain. At two years no treatment reached a clinically important difference in WOMAC pain or function, and none slowed joint space narrowing. The BMJ network meta analysis of the large trials (Wandel S et al, 2010, PMID 20847017, 10 trials, 3,803 patients) found the pain difference versus placebo was 0.3 cm on a 10 cm scale for chondroitin, well below the threshold a patient would notice, and concluded there is no clinically relevant effect on joint pain or joint space narrowing. Crucially, Wandel reports that the benefit tracks the funder: industry funded studies showed symptomatic relief and non industry funded studies showed no effect, with the independent estimate described as minute to zero. Cochrane (Singh JA et al, 2015) is the most generous read available and even it only finds a slight short term pain improvement while stating that many included studies used unsound methods. NCCIH's own summary: it is still uncertain whether glucosamine and chondroitin are helpful for knee osteoarthritis symptoms, expert bodies reach conflicting conclusions, and the American College of Rheumatology strongly recommends AGAINST glucosamine for knee osteoarthritis.
800 to 1,200 mg daily, the dose used in the trials, including GAIT which used 1,200 mg daily in three divided doses. Note that this is the dose that failed the trial.
800 to 1200 mg daily.
Generally very safe.
Pregnancy: caution
Breastfeeding: caution
Active compounds: chondroitin sulfate
Remedies using Chondroitin Sulfate · Browse by body system · Check it against what you take
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.