Ultra-D 5000™ offers (5000 IU) 125 mcg of a highly absorbable and natural source of vitamin D3 (cholecalciferol) with its key cofactors in a base of cod liver oil. The formula was designed to support the metabolism of vitamin D and to deliver a powerful mix of nutrients including magnesium, biotin, pantethine, calcium, and boron.* In addition, this product is ideal for a more aggressive vitamin D supplementation.