Vitamin D (cholecalciferol) is a useful vitamin to help speed skin regeneration and to help with skin inflammation. Vitamin D works well in synergy with essential fatty acids, as in Rose Hip and Hemp Seed oils. It is heat sensitive, so it is recommended to be added to creams and other products after they have cooled. From 0.02% to 0.05% is all that is needed. Best stored in refrigerator after opening.