NATURES SHOCK ABSORBERZipvit combines our premium Glucosamine with the finest marine sources chondroitin. Glucosamine occurs naturally in the body where it plays a role in the smooth working of the joints, and helps maintain connective tissue.Of equal importance is Chondroitin Sulphate. It is important to ote that we only use 90% marine chondroitin, sourced exclusively from fish. Many companies use low strength and far cheaper 20% strength chondroitin sourced from the cartilage of cattle. We do not believe that any bovine chondroitin can be guaranteed to be as safe as the marine source used by ZipVit. (size 00)