Double Strength Chewable Glucosamine Tablets. Veterinarian formulated, all natural active ingredient joint formula, combines chondroitin sulfate and glucosamine HCl. They are known to supply and build glycosaminoglycans (GAGS) and collagen. These are essential for rebuilding cartilage and synovial fluid. It also contains essential antioxidants. Antioxidants are know to remove damaging free radicals.