Very few foods naturally contain vitamin D, and most all D3 supplements are sourced from lanolin — the fat of lamb’s wool. These liquid drops are made from non-GMO, vegan lichen. Vitamin D3, or cholecalciferol, aids the body in absorbing phosphorus and calcium, supporting immune functions and bone health. For those who are interested in megadosing vitamin D, this product contains 100 mcg (4000 IU) vitamin D per serving.