Vitamin D3-5000: Vitamin D3 is cholecalciferol made from lanolin derived cholesterol from the wool of sheep. Vitamin D3 is the kind your body makes. Which makes it more efficient in absorption. Vitamin D2 is not the kind the body makes. Therefore, it's less efficient and you use more. It's also usually cheaper. This product is certified Kosher. One capsule provides Vitamin D3 125mcg (5000IU).