Chondroitin, a natural part of cartilage sold as a joint supplement, is used for wear-related joint disease. The strongest data show a small, slow-building easing of joint pain, most consistent with drug-grade products, though large independent studies found little or no effect. Population studies link use to fewer heart attacks, an unconfirmed signal. It is a low-risk option, but product quality varies widely. (Full Review)
| Marker | Target | Why |
|---|---|---|
| INR (warfarin users) | No established target for chondroitin; track change from the stable pre-supplement INR | Safety check: a rise changes use |
| ALT and AST (liver disease) | ALT about 7–56 U/L; AST about 10–40 U/L | Safety check: a new rise stops use |
| Joint pain score (0–100 mm visual scale) | No established target; track change from baseline | Primary response marker |
| hs-CRP | Below about 5 mg/L; track change from baseline | Inflammation marker |
| Minimum joint space width (standing knee X-ray) | No established target; track change from baseline | Structural marker |
Cadence: INR at 1–2 weeks after starting, after any dose change and 1–2 weeks after stopping; liver enzymes at 4–8 weeks in liver disease; pain and function scores monthly for the first 3 months, then at 6 months; knee X-rays every 1–2 years if structure is tracked.