Chondroitin sulfate
A major structural component of cartilage. Best evidence is in combination with glucosamine for knee osteoarthritis.
Moderate for knee osteoarthritis when combined with glucosamine (GAIT trial subgroup analysis). Effect size is small-to-modest. Strongest in moderate-severe knee OA. Effects: 8–12 weeks.
Chondroitin sulfate is a sulfated glycosaminoglycan that draws water into cartilage and gives it shock-absorbing compressive strength. As a supplement it's been studied for decades for osteoarthritis, with results mirroring glucosamine's — modest effects, more in moderate-to-severe OA than mild, and most consistently when combined with glucosamine. Bioavailability is poor (only ~12% of oral chondroitin reaches the bloodstream intact), which is part of why the effect size is modest. Generally well-tolerated, safe long-term, and cheap.
- Form
- Chondroitin sulfate sourced from bovine trachea (most common) or shark cartilage (sustainability concerns). Usually combined with glucosamine in joint formulas.
- Dose
- 800–1,200 mg/day. Often paired with 1,500 mg glucosamine sulfate.
- Timing
- With food. Split into 2–3 doses across the day.
- Schedule
- Daily, ongoing.
- Side effects
- Generally well-tolerated. Mild GI upset, nausea. Headache. Rare allergic reactions.
- Interactions
- Warfarin — can potentiate; INR monitoring. Otherwise clean.
- Contraindications
- Shellfish / shark allergy (if shark-sourced). Bovine allergy. On warfarin without monitoring. Prostate cancer history (one small study suggested chondroitin might affect outcomes — relative caution).
- Lab markers
- Not standard. Joint function tracking.
- Food sources
- Bone broth, cartilage in slow-cooked meats (shanks, oxtail, ribs with cartilage), chicken feet. Not in everyday muscle meat or plant food.
Pairs with
Glucosamine sulfate — the classic pairing, mutually reinforcing. MSM, hyaluronic acid, UC-II, collagen peptides, omega-3 (full joint stack).
within Polysaccharides & glycoconjugates