Why Choose Incite Nutrition Vitamin D3 4000iu. We carefully source our ingredients such as cholecalciferol from our trusted UK suppliers. It is also suitable for vegetarians and is Gluten free. bulking agents: calcium carbonate, microcrystalline cellulose; vitamin D preparation (cholecalciferol); anti-caking agents: rice fibre, rice extract blend (rice extract, rice hulls, gum Arabic, sunflower oil).