Chondroitin Supplements Guide (2026): Evidence, Dose & the Purity Problem

Chondroitin sulfate is usually sold alongside glucosamine for osteoarthritis. Evidence is genuinely mixed — the large GAIT trial found no overall benefit, but some pharmaceutical-grade chondroitin trials report modest pain and joint-space improvements at 1,200 mg/day. The bigger practical problem is purity: independent testing routinely finds bottles with a fraction of the labeled chondroitin, because the raw material is expensive. Below: the evidence, honest dosing, and whether stacking it with glucosamine actually helps.