Osteocare Original is the UK's no.1 bone health formula and has been scientifically developed on the basis of the very latest research to provide a rich source of calcium and co-factors including vitamin D which helps with the normal absorption of calcium by the body. Osteocare contains the preferred D3 form of Vitamin D. Vitamin D3, also known as cholecalciferol, is the form of vitamin D that is produced by the skin on exposure to sunlight. D3 is the preferred form of vitamin D because it is the specific form made in the human body and therefore more effective than D2 which is found in some supplements.