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. Calcium is carefully combined with co-factors including vitamin D, zinc and magnesium which help to maintain normal bone health