Bio-D is a high potency vitamin D product in a liquid form, providing 100iu of vitamin D3 (cholecalciferol) per drop. Vitamin D is a fat soluble nutrient that is normally combined with fats and oils to improve absorption. Vitamin D helps maintain blood levels of calcium and phosphorous. By promoting calcium absorption, vitamin D helps form and maintain strong bones, as well as working in combination with a number of other vitamins and minerals to promote bone mineralisation. Research also suggests that vitamin D has many other benefits including supporting a healthy immune system.